WindowServer+LibGUI+FontEditor: Encode special characters as UTF-8

Author: https://github.com/bugaevc
Commit: 22e6978c71
Pull-request: https://github.com/SerenityOS/serenity/pull/520
Reviewed-by: https://github.com/awesomekling

Libraries/LibGUI/GTableView.cpp

@@ -341,9 +341,9 @@ void GTableView::paint_headers(Painter& painter)
             builder.append(model()->column_name(column_index));
             auto sort_order = model()->sort_order();
             if (sort_order == GSortOrder::Ascending)
-                builder.append(" \xf6");
+                builder.append(" \xc3\xb6");
             else if (sort_order == GSortOrder::Descending)
-                builder.append(" \xf7");
+                builder.append(" \xc3\xb7");
             text = builder.to_string();
         } else {
             text = model()->column_name(column_index);