Fix links in documentation

[Jean-BaptisteC]

I have planned to fix all links in documentation.

[HolgerJeromin]

ref 6fe3387

[Jean-BaptisteC]

ref 5a2286b

[Jean-BaptisteC]

All links in documentation has been tested

[matkoniecz]

At some point I will get that dead link detector running...

This should have been detected automatically.

(I started working on it and run into bugs in libraries I was planning to use - I should look whether they fixed them or just write spider + error checker myself)

[mnalis]

At some point I will get that dead link detector running...

Something like this (have not tried)?
https://andrewwegner.com/find-broken-links-with-github-actions.html

[matkoniecz]

https://andrewwegner.com/find-broken-links-with-github-actions.html

I use broken-link-checker for now. I picked this because I'm familiar with it. It hasn't been updated since 2018, though, so in the future I may spend some time either looking for an alternative or building an alternative. For the time being though, it works just fine.

Well, for me it is not working fine - see stevenvachon/broken-link-checker#234 (it is one of projects I tried)