Fix Ctrl+click on @GDScript constants

modules/gdscript/gdscript_editor.cpp

@@ -2628,6 +2628,13 @@ Error GDScriptLanguage::lookup_code(const String &p_code, const String &p_symbol
 		}
 	}
 
+	if ("PI" == p_symbol || "TAU" == p_symbol || "INF" == p_symbol || "NAN" == p_symbol) {
+		r_result.type = ScriptLanguage::LookupResult::RESULT_CLASS_CONSTANT;
+		r_result.class_name = "@GDScript";
+		r_result.class_member = p_symbol;
+		return OK;
+	}
+
 	GDScriptParser p;
 	p.parse(p_code, p_base_path, false, "", true);