modules/qt: Type anotations and cleanups
modules/qt: Type anotations and cleanups

This adds a number of missing type annotations to existing functions,
and makes a few members protected instead of public, as they were never
meant to be public

mesonbuild/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,jpakkane/meson,jpakkane/meson,mesonbuild/meson,pexip/meson,pexip/meson,pexip/meson,jpakkane/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,pexip/meson