docs: sprucing up docs, esp. reference doc generation

[filmaj]

• dynamically load generated sidebar items - requires a bit of gymnastics, because TypeDoc, which imports+parses TypeScript code to generate docs from source code comments, runs in parallel during docusaurus sidebar generation. As a result, sometimes there can be race-condition-like errors where the TypeDoc generation is not complete before the sidebar generation kicks off. Code was added to, basically, wait for the relevant sub-package TypeDoc routines to complete before finalizing the sidebar items.
• add biome / linting to docs folder
• lint during docs CI
• tweak generated reference documentation styles (tables instead of lists where possible)

Doing this as part of a an initial pass to learn the docusaurus ropes as I inch towards applying the same thing to bolt-js docs.

I left some in-line comments with screenshots of relevant changes. The big visual change is using tables for API references instead of bulleted lists: I think this is more visually pleasing and also scalable as we add more content to the docs.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.74%. Comparing base (da9100d) to head (791df25). Report is 6 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2070 +/- ## ======================================= Coverage 91.74% 91.74% ======================================= Files 38 38 Lines 10081 10083 +2 Branches 631 631 ======================================= + Hits 9249 9251 +2 Misses 820 820 Partials 12 12 ``` | [Flag](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | Coverage Δ | | |---|---|---| | [cli-hooks](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `95.23% <ø> (ø)` | | | [cli-test](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `95.69% <ø> (+<0.01%)` | :arrow_up: | | [oauth](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `77.39% <ø> (ø)` | | | [socket-mode](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `58.22% <ø> (ø)` | | | [web-api](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `96.89% <ø> (ø)` | | | [webhook](https://app.codecov.io/gh/slackapi/node-slack-sdk/pull/2070/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi) | `96.65% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=slackapi#carryforward-flags-in-the-pull-request-comment) to find out more.

[filmaj]

Odd, docs building seems to fail in CI but runs fine for me locally 🤔 need to investigate more.