Add slowmode error

gramjs_generator/data/errors.csv

@@ -228,6 +228,7 @@ SESSION_PASSWORD_NEEDED,401,Two-steps verification is enabled and a password is
 SESSION_REVOKED,401,"The authorization has been invalidated, because of the user terminating all sessions"
 SHA256_HASH_INVALID,400,The provided SHA256 hash is invalid
 SHORTNAME_OCCUPY_FAILED,400,An error occurred when trying to register the short-name used for the sticker pack. Try a different name
+SLOWMODE_WAIT_X,420,A wait of {seconds} seconds is required before sending another message in this chat
 START_PARAM_EMPTY,400,The start parameter is empty
 START_PARAM_INVALID,400,Start parameter invalid
 STICKERSET_INVALID,400,The provided sticker set is invalid

gramjs_generator/parsers/errors.js

@@ -27,7 +27,10 @@ const getClassName = errorCode => {
     }
 
     return snakeToCamelCase(
-        errorCode.replace('FIRSTNAME', 'FIRST_NAME').toLowerCase(),
+        errorCode
+            .replace('FIRSTNAME', 'FIRST_NAME')
+            .replace('SLOWMODE', 'SLOW_MODE')
+            .toLowerCase(),
         'Error'
     );
 };