Add few more Qt-related file extensions to known ones:

.pri: They are very closed to .pro files.
      Unfortunately .pri can also refers to binary files
      in Window app context, hence it is added as Uncommentable.

.qrc: Those are Qt XML files containing indexes to resource files.
      Added as Uncommentable because Qt Creator IDE rewrites the file
      when saving, loosing copyrights each time therefore loosing history.

.qss: Qt Style Sheet, based on CSS file format.

.ui: Qt user interface definition file, XML.
     Added as Uncommentable because ui files are overwritten by
     Qt Creator upon saving which looses copyright history.

Signed-off-by: Anthony Loiseau <anthony.loiseau@allcircuits.com>

As noted by Carmen Bianca BAKKER within fsfe#755 review,
reuse automatically creates a .license for binary files
ignoring known file extension map.

Therefore binary Windows app .pri file is not an issue
to mark .pri files as python-like files.

I tested with two pri files: one legitimate Qt pri file (text)
and one fake binary pri file. Reuse actually did things as expected,
injecting license in text pri file and as a separate file for the
binary pri file.

Attribution: Carmen Bianca BAKKER