Streamline Comment fields of KCMs

This patch applies a common language and type-setting to the
systemsettings modules in kde-workspace.

Considerations:
- The comment field might repeat the name, or give more detail about the
specific settings on this page, this makes sense with how
systemsettings and kcmshell present it
- Mentioning the words settings, configure, options, etc. is avoided --
it is clear from the context that these are settings and options.
- Title-case throughout in line with human interface guidelines, see
http://techbase.kde.org/Projects/Usability/HIG/Capitalization
- The comment ends up being the title, so the
- tech slang is avoided as much as possible, but left in where really
necessary (hi Phonon), there were a few mentions of ~"KDE Settings",
which don't make sense in a properly branded universe.
- I've left the Name field "mostly untouched", as that one is key for
the user to find the right module in systemsettings' icon view and in
the sidebars

The same treatment needs to be done for a bunch of other KCMs that we
end up installing from other repos. This is a good start, however.

REVIEW:118290