feat(language-service): autocompletion for the component not imported

[ivanwonder]

This PR allows the language service to suggest imports for all directives returned from the compiler, and generate the TypeScript module import and the decorator import when the component is selected by the user.

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PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.io application / infrastructure changes
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

[ivanwonder]

https://github.com/angular/angular/blob/1872fcd8e09fefb52f9b36e8261702cd6fb03f85/packages/compiler-cli/src/ngtsc/typecheck/src/checker.ts#L766_L771

This will be a bug if two components have the same selector name. I think we can fix this later.

[dylhunn]

Really nice work, thank you for making this improvement! I didn't realize you could provide actions alongside completions like this, and good work factoring out the common code.

reviewed-for: fw-compiler, language-service

[ivanwonder]

@dylhunn

I find a bug here. I only tested it in the HTML file, It doesn't work for the template in the ts file because the code action breaks the rule of additionalTextEdits, additional text edits should be used to change text unrelated to the current cursor position, but the auto-import code action change range includes the template where the current cursor is.

I think the code action for auto-import should only touch the imports array instead of the whole component decorators. I will try to fix this.

Sorry about this.