TextEditor: Add some logging for code folding

Change-Id: I95f6c1b370d458602d9d97e36b21d61c1d261e59
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/texteditor/texteditorconstants.cpp

@@ -125,4 +125,9 @@ TextStyle styleFromName(const char *name)
 }
 
 } // namespace Constants
+
+namespace Internal {
+Q_LOGGING_CATEGORY(foldingLog, "qtc.editor.folding", QtWarningMsg)
+} // namespace Internal
+
 } // namespace TextEditor