Fixes of all kind
Fixes after review
minor #3595 Collection of fixes and improvements (bicpi)

This PR was merged into the 2.3 branch.

Discussion
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Collection of fixes and improvements

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | -

This PR fixes all kind of typos, formatting and code issues.
It also adds some missing code blocks and notes or improvements.

Thanks for your review and please let me know if you see something wrong.

Commits
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56e475c Fixes after review
8d4f444 Fixes of all kind