[Bug driver/31357] document that --help and --help= options cannot be combined.

[sandra at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31357

sandra at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |sandra at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #5 from sandra at gcc dot gnu.org ---
I've committed the patch with a minor copy-edit.  

I apologize for screwing up the author attribution in the commit message; I
corrected the ChangeLog.  :-(