It turns out checking changes on `.inc.qhelp` files is a bit trickier,
as we need to first find which `qhelp` files use them. The previous
iteration of this script was working under the assumption that
`.inc.qhelp` files were only included from the current or a parent
path, but this turns out to be wrong.
This time around, if we are asked to check one or more `.inc.qhelp`
files we build an include map from all `qhelp` files and run the help
generator on the `qhelp` files actually including them.