Add the name of the class/enum/etc in the page title

Currently, all the title says is "discord.js", the version number, and then "discord.js" again.
This is not helpful at all when using the browsing history or when you have several tabs.

It would be much better if there were, for example, `User:class | discord.js (version)`, `UserFlags:Enum | discord.js (version)`, etc.

I remember that this had already been an issue in the past, and it had been fixed, so that's a regression.