Updated dircycle plugin to have dirhistory-like functions to go up a directory and go down to the first child directory

[kayhangultekin]

Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
• I have read the contribution guide and followed all the instructions.
• The code follows the code style guide detailed in the wiki.
• The code is mine or it's from somewhere with an MIT-compatible license.
• The code is efficient, to the best of my ability, and does not waste computer resources.
• The code is stable and I have tested it myself, to the best of my abilities.
• If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

• Update dircycle.plugin.zsh to create two new functions: insert-cycledup, which changes directory up and insert-cycleddown, which changes directory into the first child directory. These were inspired by existing functions in dirhistory plugin.

Other comments:

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