Implemented generic for loops

src/Diagnostics/DiagnosticCode.hpp

@@ -26,7 +26,8 @@ namespace Porygon::Diagnostics {
         InvalidTypeName,
         UserDataFieldNoGetter,
         UserDataFieldNoSetter,
-        NumericalForArgumentNotANumber
+        NumericalForArgumentNotANumber,
+        CantIterateExpression
     };
 }
 #endif //PORYGONLANG_DIAGNOSTICCODE_HPP

src/Diagnostics/DiagnosticsHolder.cpp

@@ -69,6 +69,7 @@ std::string SeverityToString(DiagnosticSeverity s){
         case DiagnosticSeverity::Info: return "Info";
         case DiagnosticSeverity::Warning: return "Warning";
         case DiagnosticSeverity::Error: return "Error";
+        default: throw;
     }
 }