[docs] Add rule short code to mkdocs tags (#14040)
## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
This PR updates the metadata in the YAML frontmatter of the mkdocs
documentation to include the rule short code as a tag, so it can be
easily searched.
Ref: #13684
## Test Plan
<!-- How was it tested? -->
This has been tested locally using the documentation provided
[here](https://docs.astral.sh/ruff/contributing/#mkdocs) for generating
docs.
This generates docs that now have the tags section:
```markdown
---
description: Checks for abstract classes without abstract methods.
tags:
- B024
---
# abstract-base-class-without-abstract-method (B024)
... trimmed
```
I've also verified that this gives the ability to get straight to the
page via search when serving mkdocs locally.
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
