Fix minor typo in buildifier/README.md

[ArtifyCZ]

Buildtools PR checklist

• The code in this PR is covered by unit/integration tests.
• I have tested these changes and provide testing instructions below.
• I have either responded to, or resolved all Gemini comments on the PR.
• I have read Google Eng Practices on Small Changes, this PR either follows these guidelines or the description provides reasoning for why they can not be followed.

Description

What does this PR do? Please follow Google Eng Practices - Description

I fixed minor typos in README.md

I know this is really small patch. But personally, seeing typos quite irritates me.

Thank you for developing this project!

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Steps to reproduce / test the PR changes (if anything besides unit tests).

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[gemini-code-assist]

Code Review

This pull request makes minor grammatical corrections to the buildifier/README.md file. The reviewer suggested further refinements to the phrasing for better conciseness and readability, providing a specific code suggestion to revert one change and simplify another.