Clang: Move unexported classes to Internal

Change-Id: I3ea197b734f146d4b11431aaf927aed9be7d8756
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/plugins/clangcodemodel/clangeditordocumentparser.cpp

@@ -26,6 +26,7 @@
 #include "clangeditordocumentparser.h"
 
 namespace ClangCodeModel {
+namespace Internal {
 
 ClangEditorDocumentParser::ClangEditorDocumentParser(const QString &filePath)
     : BaseEditorDocumentParser(filePath)
@@ -46,4 +47,5 @@ void ClangEditorDocumentParser::updateImpl(const QFutureInterface<void> &,
     setState(state_);
 }
 
+} // namespace Internal
 } // namespace ClangCodeModel