Add scripts to run linting on only modified files

[chatton]

Description

I found running the existing make lint-fix and make docs-lint take some time to run as they are currently formatting all files in the repo. This PR adds an additional command which formats only the relevant files changed.

closes: N/A

Commit Message / Changelog Entry

N/A

see the guidelines for commit messages. (view raw markdown for examples)

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md).
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards and Go style guide.
• Wrote unit and integration tests.
• Updated relevant documentation (docs/) or specification (x/<module>/spec/).
• Added relevant godoc comments.
• Provide a commit message to be used for the changelog entry in the PR description for review.
• Re-reviewed Files changed in the Github PR explorer.
• Review Codecov Report in the comment section below once CI passes.

[crodriguezvega]

Nice!

[damiannolan]

Yeet