LibCpp: Add 'Namespace' and 'Member' declaration types

Author: https://github.com/itamar8910
Commit: b87791cada
Pull-request: https://github.com/SerenityOS/serenity/pull/6216

Userland/Libraries/LibGUI/AutocompleteProvider.h

@@ -69,6 +69,8 @@ public:
         Class,
         Variable,
         PreprocessorDefinition,
+        Namespace,
+        Member,
     };
 
     struct Declaration {