ui: improved code snippet location clicks

* activate token of most nested location
* show parts of locations with start or end outside of snippet
* (fix for multiple parsing of function and method bodies)

src/app/qt/element/QtCodeSnippet.h

@@ -70,6 +70,8 @@ private:
 	};
 
 	int toTextEditPosition(int lineNumber, int columnNumber) const;
+	int startTextEditPosition() const;
+	int endTextEditPosition() const;
 
 	QtCodeView* m_parentView;
 	QtHighlighter* m_highlighter;