The goal was a single page documentation on expression
One approach could have been about using scripts/process_function_template.py
and/or files in resources/function_help/json/
. As there is no link between groups and functions documented in these json files, you need to look for the relation in the source src/core/expression/qgsexpressionfunction.cpp
. You would also need to manage translations. FYI, all paths are relative to the root of the source code repo.
So, instead we've made the choice to use HTML generated doc for expressions from PyQGIS docs. It works for any languages