chore: add docs practices mention in the checklist

[LesnyRumcajs]

Summary of changes

Changes introduced in this pull request:

• added mention to the docs standard in Notion. If need be (aka we have more than one external contributor per quarter), we can later make it public by putting said document in GH.

Reference issue to close (if applicable)

Closes

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.