feat(linter): add vitest/prefer-lowercase-title rule

[taearls]

This pull request implements the vitest/prefer-lowercase-title rule.

Since there was an existing jest rule with this title, I followed the existing pattern in no-unused-vars to group the jest and vitest rules together in a shared module. I used the existing jest/prefer-lowercase-title documentation as a base and modified it where it seemed appropriate. I added a jest and vitest snapshot suffix for each respective test suite.

One item I wasn't 100% about is adding bench to the jest test names. Without this change, the vitest test suite fails because of this check which validates that we're only parsing valid jest functions from a detected jest file. The unit tests that are sourced from the vitest plugin are all read by the linting host as jest-like files, so adding bench as a "valid" jest method allows us to lint a unit test using this keyword. This seemed to me like the least invasive solution to accommodate the new rule without breaking any existing code, but I'm certainly open to alternatives.

[graphite-app]

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

• 0-merge - adds this PR to the back of the merge queue
• hotfix - for urgent hot fixes, skip the queue and merge this PR next

You must have a Graphite account in order to use the merge queue. Sign up using this link.

An organization admin has enabled the Graphite Merge Queue in this repository.

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

[codspeed-hq]

CodSpeed Performance Report

Merging #8152 will not alter performance

_{Comparing taearls:tyler/vitest-prefer-lowercase-title (16216ed) with main (d8d2ec6)}

Summary

✅ 29 untouched benchmarks

[taearls]

I noticed the VITEST_COMPATIBLE_JEST_RULES set and added prefer-lowercase-title there. this also updated my snapshot test for the vitest unit tests with the correct plugin name.

[camc314]

Thanks!