D45708: [NFC] Remove doxygen brief tag from BasicBlock.h

[via llvm-commits]

I diffed the two outputs and also pulled up the text in a browser.  I do not see any significant changes in browser, and there wasn't.  However, I am happy to revert if any noticeable changes are witnessed.  I see multiline/paragraph text in the output.

> -----Original Message-----
> From: Matthias Braun via Phabricator <reviews at reviews.llvm.org>
> Sent: Wednesday, April 18, 2018 1:08 AM
> To: Davis, Matthew <Matthew.Davis at sony.com>; aprantl at apple.com
> Cc: matze at braunis.de; llvm-commits at lists.llvm.org
> Subject: [PATCH] D45708: [NFC] Remove doxygen brief tag from BasicBlock.h
> 
> MatzeB added a comment.
> 
> I am pretty sure this is not correct: Autobrief is stupid and stops at the first dot
> or at the line ending AFAIK. This means when the first sentence stretches over
> more than 1 line you still need need `\brief`. So a bunch of the changes here
> appear invalid to me, please check the doxygen output and revert if necessary.
> 
> 
> Repository:
>   rL LLVM
> 
> https://reviews.llvm.org/D45708
> 
>