Add KDE Platform to known distributions

[ykgmfq]

The platform does not specify a pretty name yet, so that remains Unknown for now. I will see if I can get a pretty name into upstream.

[The-Compiler]

I'm a bit surprised that this works, with the dots in the enum name - does it?

[ykgmfq]

e=Enum('test',['a','b.c']) 
e.a                                                                                  
<test.a: 1>

e.b.c
AttributeError: b

e['b.c']                                                                             
<test.b.c: 2>

It apparently does work dependent on how you access it. The code in version.py works anyways...

[ykgmfq]

I could alternatively use id_mappings to get rid of the dots.

[The-Compiler]

Thanks! I ended up doing that (and adding a test) in b43e54d.

[ykgmfq]

Upstream change for the pretty name: https://invent.kde.org/kde/flatpak-kde-runtime/merge_requests/1

[The-Compiler]

Good idea! I also added a proper fallback on NAME if PRETTY_NAME isn't set: 88f5433