Dear Maintainer,

Pressing F1 key fails to open help, as no help docs is built as part of the
build.

Refer https://gitlab.gnome.org/GNOME/gnome-builder/-/issues/2364.

I did the following changes to debian build on my system.

1. Added "-Dhelp=true" in "debian/rules".
2. Installed "python3-sphinx-rtd-theme" dependency, which was needed to build
the Sphinx help docs.
3. Added "usr/share/doc" to "debian/gnome-builder.install"

And built .deb and installed and now help opens fine.