Version-specific name of qch file in packages is inconvenient

The .qch file that we currently include in packages has a version-specific name like CMake-3145.qch. When using tools like Qt Creator, you can point it at this .qch file and get nice docs directly integrated into the IDE. Unfortunately, when you update CMake, you lose the link to the .qch file because the file name changes, so you then have to go and setup the documentation again. This will be particularly annoying for users of the upcoming CMake snap, since updates will typically be enabled by default, so documentation could appear to suddenly stop working without warning whenever an update is performed in the background.