RGB does not work for network quit messages

[kakduman]

Describe the bug
RGB codes do not work for network quit messages. It works fine for network join messages.

To Reproduce
Steps to reproduce the behavior:

1. Set the joinmessages file to https://pastebin.com/tDCti9En.
2. See error: join messages are green (expected), but quit messages are &4, even though they use the same color code as join messages.

[OllieMartin]

This has been fixed, it was some very old legacy code preventing it from working 👍
Will be released in the next beta of 1.10 (beta 4)