Fixed SD2-473. A KeyNotFound exception is no longer thrown if the highlighting strategy does not contain a LineComment property.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@540 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Libraries/ICSharpCode.TextEditor/Project/Src/Actions/MiscActions.cs

@@ -287,7 +287,7 @@ namespace ICSharpCode.TextEditor.Actions
 			}
 			
 			string comment = null;
-			if (textArea.Document.HighlightingStrategy.Properties["LineComment"] != null) {
+			if (textArea.Document.HighlightingStrategy.Properties.ContainsKey("LineComment")) {
 				comment = textArea.Document.HighlightingStrategy.Properties["LineComment"].ToString();
 			}