This removes the specific version from the control-by-control example
and thus makes it similar to the other examples where we use a relative
path. `get-started.md` and the *.html files will still show how this can
be done with a specific version.
Build-bot: skip
Test-bot: skip
Note: build.sh updated to make sure that test:help build action:target
doesn't also call test.sh by adding `:_all` meta-target.
Note: CI will need a new help-keyman-com.sh build step to deploy web
engine help.
Fixes: #12347
