Fix constant tag documentation in C# bindings generator

modules/mono/editor/bindings_generator.cpp

@@ -387,7 +387,7 @@ String BindingsGenerator::bbcode_to_xml(const String &p_bbcode, const TypeInterf
 					xml_output.append(link_target);
 					xml_output.append("</c>");
 				}
-			} else if (link_tag == "const") {
+			} else if (link_tag == "constant") {
 				if (!target_itype || !target_itype->is_object_type) {
 					if (OS::get_singleton()->is_stdout_verbose()) {
 						if (target_itype) {