[Qt-creator] How to build Qt Creator documentation from the sources

[Artur Shepilko]

I normally do:

cd build-qtcreator
make docs
ls share/doc/qtcreator/qtcreator.qch

This expects Qt doc files properly installed. In older Qt versions
there was a missing link to global .qdocconf, so it'd show an error
and would require one to manually create the missing link. In recent
versions it builds all the way as is. It does show a while bunch of
warnings though, but I guess it's "by design".

This may be helpful
[https://doc-snapshots.qt.io/qtcreator-extending/qtcreator-documentation.html]