[PATCH][wwwdocs][Arm][AArch64] Update changes with new features and flags.

[Gerald Pfeifer]

On Wed, 6 Feb 2019, Tamar Christina wrote:
> I've updated the patch with your suggested changes and have grouped
> the Arm and AArch64 targets a bit.

Thanks, Tamar!

> Ok for commit?

Yes, I had meant to imply this in my original review. :-)

Only note is that this seems to hop from <h3> to <h5>, skipping <h4>?

Gerald