docs: css.modules.localsConvention is null by default, fix #5650

[ydcjeff]

Description

css.modules.localsConvention is null by default. This change was made in fee7393 and docs update missed in e4f78ef.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[ydcjeff]

Btw, netlify docs preview isn't running on PR?

[patak-dev]

Btw, netlify docs preview isn't running on PR?

It is only running against main, and they aren't public AFAIK. It would be good to get more direct feedback though