Remove select-get from Language Reference Docs

[tbrinkman3]

Already documented in the Book. Removing duplicate location. See: #1744

[fdncred]

I don't think it's a good idea to remove sections from the language guide because they're documented in the book. The language guide performs a slightly different task than the book and things like this should be minimally documented in the guide.

[NotTheDr01ds]

@fdncred To be fair, I added that page and TODO in the Language Guide a while back, then added the select/get info to the Book but forgot to remove it from the Language Guide. If there's something specific we need in the language guide regarding this, then I'm okay with leaving the placeholder, but it's my "fault" it's in there in the first place, so I'm okay with it coming out if you are.

[fdncred]

I think the language guide should every language related item in it. Even if it's just a high-level blurb that points to more in-depth documentation.