docs(contributing): improve instructions for batch applying review suggestions

[HonkingGoose]

Changes

• You can "commit as often as you want", but we still want you to batch apply review suggestions
• Small rewrite of the section about applying review suggestions

Context

A new contributor read "commit as often" to also mean one commit per review suggestion:

• feat(manager): Cloud Native Buildpacks project descriptor manager #30799 (comment)

So I'm improving the instructions in the docs. 😄

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[renovate-release]

🎉 This issue has been resolved in version 38.40.0 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)
• 38.40.0

Your semantic-release bot 📦🚀