[keditfiletype] Set proper name in desktop file

This is shown in the task manager tooltip so use a user-suitable name instead of the internal one

keditfiletype/org.kde.keditfiletype.desktop

 [Desktop Entry]
-Name=keditfiletype
+Name=File Type Editor
 Name[az]=keditfiletype
 Name[ca]=keditfiletype
 Name[ca@valencia]=keditfiletype