text: Title: Replace `git checkout` with `git switch` where possible
  Body: ### Description:
  
  A minor suggestion for a good first issue, which might improve our documentation from the perspective of contributors which are new to git. 
  
  **If you are a new contributor looking for a good first issue**: if this issue is more than a few days old and there hasn't been disagreement, please feel welcome to go ahead and [create a pull request](https://scikit-image.org/docs/dev/development/contribute.html). 
  
  The task: 
  - replace every occurrence of `git checkout <existing-branch>` with `git switch <existing-branch>`
  - replace every occurrence of `git checkout -b <new-branch>` with `git switch -c <new-branch>`
  
  in our documentation (files ending in `.md`, `.rst`, and `.txt`). Don't hesitate to reach out before if you have questions. :)