Fix build with new sphinx

[drdanz]

Following changes are done to build with new sphinx:

• Replaced htmlescape with html.escape
• Change import path for QtHelpBuilder and keep the older one as fallback
• Change number of return values in call method

Forwarded from https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=997429

[drdanz]

For reference, this file was originally imported from CMake

https://gitlab.kitware.com/cmake/cmake/-/blob/master/Utilities/Sphinx/cmake.py

The original files received several patches since 2015, so it might be worth updating it.

GitLab

Utilities/Sphinx/cmake.py · master · CMake / CMake

CMake, the cross-platform, open-source build system.

[traversaro]

Thanks!