Can not add words to dictionary

[FalcoGer]

Describe the bug
When using coc.nvim with the coc-ltex module, I can not add words to the user's dictionary.

I usually run vim from whatever path I'm currently in, and I don't want random .vscode directories pop up all over my filesystem, so I have set the configuration targets to be user.

    "ltex.configurationTarget": {
        "dictionary": "user",
        "disabledRules": "user",
        "hiddenFalsePositives": "user"
    },

But then when I try to add a word to the dictionary, I get this exception:

2023-11-16T22:53:44.833 ERROR (pid:1287619) [server] - unhandledRejection  Promise {
  �[36m<rejected>�[39m TypeError: Cannot add property en-US, object is not extensible
      at CommandHandler.<anonymous> (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17685:40)
      at Generator.next (<anonymous>)
      at /home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17111:71
      at new Promise (<anonymous>)
      at __webpack_modules__.1216.__awaiter (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17107:12)
      at CommandHandler.addToLanguageSpecificSettingInternalSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17671:16)
      at CommandHandler.addToLanguageSpecificSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17647:18)
      at CommandHandler.addToDictionary (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17609:14)
      at HR.execute (/home/user/.vim/plugged/coc.nvim/build/index.js:66:3095)
      at BR.executeCommand (/home/user/.vim/plugged/coc.nvim/build/index.js:66:4200)
} TypeError: Cannot add property en-US, object is not extensible
    at CommandHandler.<anonymous> (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17685:40)
    at Generator.next (<anonymous>)
    at /home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17111:71
    at new Promise (<anonymous>)
    at __webpack_modules__.1216.__awaiter (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17107:12)
    at CommandHandler.addToLanguageSpecificSettingInternalSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17671:16)
    at CommandHandler.addToLanguageSpecificSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17647:18)
    at CommandHandler.addToDictionary (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17609:14)
    at HR.execute (/home/user/.vim/plugged/coc.nvim/build/index.js:66:3095)
    at BR.executeCommand (/home/user/.vim/plugged/coc.nvim/build/index.js:66:4200)

I have tried setting an external file to be used with

    "ltex.dictionary": {
        "en-US": [
            ":~/.vim/ltex/dict/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/dict/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/dict/en_GB.txt"
        ]
    },
    "ltex.enabledRules": {
        "en-US": [
            ":~/.vim/ltex/enabled/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/enabled/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/enabled/en_GB.txt"
        ]
    },
    "ltex.disabledRules": {
        "en-US": [
            ":~/.vim/ltex/disabled/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/disabled/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/disabled/en_GB.txt"
        ]
    },
    "ltex.hiddenFalsePositives": {
        "en-US": [
            ":~/.vim/ltex/hidden/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/hidden/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/hidden/en_GB.txt"
        ]
    },

but then I get a different exception

2023-11-16T22:54:45.990 ERROR (pid:1287619) [server] - unhandledRejection  Promise {
  �[36m<rejected>�[39m TypeError: Cannot assign to read only property 'en-US' of object '[object Object]'
      at CommandHandler.<anonymous> (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17685:40)
      at Generator.next (<anonymous>)
      at /home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17111:71
      at new Promise (<anonymous>)
      at __webpack_modules__.1216.__awaiter (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17107:12)
      at CommandHandler.addToLanguageSpecificSettingInternalSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17671:16)
      at CommandHandler.addToLanguageSpecificSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17647:18)
      at CommandHandler.addToDictionary (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17609:14)
      at HR.execute (/home/user/.vim/plugged/coc.nvim/build/index.js:66:3095)
      at BR.executeCommand (/home/user/.vim/plugged/coc.nvim/build/index.js:66:4200)
} TypeError: Cannot assign to read only property 'en-US' of object '[object Object]'
    at CommandHandler.<anonymous> (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17685:40)
    at Generator.next (<anonymous>)
    at /home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17111:71
    at new Promise (<anonymous>)
    at __webpack_modules__.1216.__awaiter (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17107:12)
    at CommandHandler.addToLanguageSpecificSettingInternalSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17671:16)
    at CommandHandler.addToLanguageSpecificSetting (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17647:18)
    at CommandHandler.addToDictionary (/home/user/.config/coc/extensions/node_modules/�[4mcoc-ltex�[24m/dist/extension.js:17609:14)
    at HR.execute (/home/user/.vim/plugged/coc.nvim/build/index.js:66:3095)
    at BR.executeCommand (/home/user/.vim/plugged/coc.nvim/build/index.js:66:4200)
2023-11-16T22:54:46.258 INFO (pid:1287619) [attach] - receive notification: highlight []

Stepse to reproduce
Steps to reproduce the behavior:

1. Open file with grammar mistake in nvim
2. If required, enable coc-ltex with CocList extensions, select coc-ltex and enter
3. Wait for the diagnostics to populate
4. Do a coc-code action at cursor
5. Select Add to dictionary

Expected behavior
One of the following:

• The external file listed in CocConfig is changed
• CocConfig is changed
• A file in ~/.config/Code/User/globalStorage/valentjn.vscode-ltex/ is created and changed

Sample document

This is a unknownword.

LTeX configuration

```json
    "ltex.enabled": [
        "bibtex",
        "context",
        "context.tex",
        "html",
        "latex",
        "markdown",
        "org",
        "restructuredtext",
        "rsweave",

        "text",

        "shellscript",
        "c",
        "csharp",
        "cpp",
        "javascript",
        "lua",
        "perl",
        "php",
        "powershell",
        "python",
        "ruby",
        "rust",
        "sql",
        "verilog",
        "vb"
    ],
    "ltex.language": "en-US",
    "ltex.sentenceCacheSize": 2000,
    "ltex.dictionary": {
        "en-US": [
            ":~/.vim/ltex/dict/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/dict/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/dict/en_GB.txt"
        ]
    },
    "ltex.enabledRules": {
        "en-US": [
            ":~/.vim/ltex/enabled/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/enabled/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/enabled/en_GB.txt"
        ]
    },
    "ltex.disabledRules": {
        "en-US": [
            ":~/.vim/ltex/disabled/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/disabled/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/disabled/en_GB.txt"
        ]
    },
    "ltex.hiddenFalsePositives": {
        "en-US": [
            ":~/.vim/ltex/hidden/en_US.txt"
        ],
        "de-DE": [
            ":~/.vim/ltex/hidden/de_DE.txt"
        ],
        "en-GB": [
            ":~/.vim/ltex/hidden/en_GB.txt"
        ]
    },
    "ltex.configurationTarget": {
        "dictionary": "user",
        "disabledRules": "user",
        "hiddenFalsePositives": "user"
    },
    "ltex.additionalRules.enablePickyRules": true,
    "ltex.additionalRules.motherTongue": "de-DE",
    "ltex.ltex-ls.logLevel": "warning",
    "ltex.completionEnabled": true,
    "ltex.diagnosticSeverity": {"PASSIVE_VOICE": "hint", "default": "information"},
    "ltex.checkFrequency": "edit",
    "ltex.clearDiagnosticsWhenClosingFile": true,
    "ltex.statusBarItem": false,
    "ltex.trace.server": "off",

LTeX LS log
Paste the log (output) of LTeX LS here:

See above

Version information
List here the version information of the relevant software.

• Operating system: Linux <hostname> 5.15.0-84-generic #93-Ubuntu SMP Tue Sep 5 17:16:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux (Ubuntu Mate 22.04)
• ltex-ls: 13.1.0 (according to ~/.config/coc/extensions/node_modules/coc-ltex/package.json)
• Java:

openjdk 18.0.2-ea 2022-07-19
OpenJDK Runtime Environment (build 18.0.2-ea+9-Ubuntu-222.04)
OpenJDK 64-Bit Server VM (build 18.0.2-ea+9-Ubuntu-222.04, mixed mode, sharing)

Additional context/information
Would enjoy documentation on how to set the path for the settings file.