fix(mango): use xkb brief for shortDescription in language module

Remove leftover unconditional assignment that clobbered the value
computed from rxkb_layout_get_brief() with short_name, which made
short_description always equal short_name and defeated
format-<shortDescription> / {shortDescription}.

src/modules/mango/language.cpp

@@ -110,8 +110,6 @@ Language::Layout Language::getLayout(const std::string& fullName) {
           short_description = short_name;
         }
 
-        short_description = short_name;
-
         Layout info{desc, short_name, variant, short_description};
         return info;
       }