Fix some typos

[ydah]

This PR is fix some typos:

• "formater" -> "formatter"
• "criticed" -> "criticized"
• "indepedent" -> "independent"
• "seperated" -> "separated"
• "existant" -> "existent"

Commits are separated for clarity of differences, but will be squashed if necessary.

Check list:

• [x] Add an entry to the changelog
• [x] Squash all commits into a single one
• [x] Describe your PR, link issues, etc.

[ydah]

@etagwerker Thank you for your review! I added it to changelog, resolved the conflict, and then squashed the commit according to the checklist.