Updated C# example for method AddPropertyInfo

(cherry picked from commit 694f280acd)

doc/classes/ProjectSettings.xml

@@ -43,8 +43,8 @@
 				var propertyInfo = new Godot.Collections.Dictionary
 				{
 				    {"name", "category/propertyName"},
-				    {"type", Variant.Type.Int},
-				    {"hint", PropertyHint.Enum},
+				    {"type", (int)Variant.Type.Int},
+				    {"hint", (int)PropertyHint.Enum},
 				    {"hint_string", "one,two,three"},
 				};