Discord.js: Guild.createInvite method isn't documented

[ethanent]

Please describe the problem you are having in as much detail as possible:
In the official discord.js docs, the Guildclass (link) doesn't contain documentation for the Guild.createInvite method.

Further details:

• discord.js version: 11.3.2
• node.js version: 8.9.4
• Operating system: OS X El Capitan
• Priority this issue should have – please be realistic and elaborate if possible: 4 on a scale of 1-10, 10 being most important. 😁

• [ ] I found this issue while running code on a __user account__
• [ ] I have also tested the issue on latest master, commit hash:

[ethanent]