ui: Improved user experience of error display

* label errors as errors instead of references in file snippet headers
* show number of fatal errors in file snippet headers as well
* only show the first 10 error snippets open, remaining collapsed
* don't show status message after parsing in red on errors
* don't show stats of parsing when project was only loaded

src/lib_gui/qt/element/QtCodeFile.h

@@ -14,6 +14,7 @@
 #include "utility/messaging/type/MessageWindowFocus.h"
 #include "qt/utility/QtThreadedFunctor.h"
 
+#include "data/ErrorInfo.h"
 #include "component/view/helper/CodeSnippetParams.h"
 
 class QLabel;
@@ -42,7 +43,7 @@ public:
 	const std::vector<Id>& getActiveLocalSymbolIds() const;
 	const std::vector<Id>& getFocusedTokenIds() const;
 
-	const std::vector<std::string>& getErrorMessages() const;
+	std::vector<std::string> getErrorMessages() const;
 	bool hasErrors() const;
 
 	void addCodeSnippet(const CodeSnippetParams& params);