Fix typos, remove inapplicable instructions from dev docs

[m-fila]

Fixing a few small typos. Removing instruction about pre-commit since there is no pre-commit config for this repo. Also removing part about updating Changelog.md since it already isn't followed 🙃

Related issues

There is no related issue.

Checklist

• Tests are passing
• Docs were updated and workflow is passing

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.38%. Comparing base (b9b9d8f) to head (b5f6300).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #36   +/-   ##
=======================================
  Coverage   93.38%   93.38%           
=======================================
  Files           5        5           
  Lines         136      136           
=======================================
  Hits          127      127           
  Misses          9        9           

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