Add documentation for how to use features

[meaghanlewis]

Purpose

The purpose of this issue is to identify where documentation needs to be added. We currently have documentation for contributing, developers, and getting started.

Features include:

• Creating a repository ✅
• Publishing a repository ✅
• Pull Request related
  • viewing PR's ✅
  • inline comments ✅
  • PR reviews
  • checks and statuses
  • creating PR's ✅
• Forking
• Using the GitHub context menu
  • Open on GitHub
  • Blame
  • Creating a Gist ✅
  • Open from clipboard

[meaghanlewis]

Documentation was updated in this PR: #1943

I'll add documentation for the items without checkmarks.