Contributing section docs

[pilosus]

Change Summary

Minor updates to docs' Contributing section

Related issue number

#441

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• HISTORY.rst has been updated
  • if this is the first change since a release, please add a new section
  • include the issue number or this pull request number #<number>
  • include your github username @<whomever>

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@3a33d8d). Click here to learn what that means.
The diff coverage is n/a.

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