[Bug preprocessor/77810] provide format_inform_at_substring to go with format_warning_at_substring

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77810

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-05-17
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=77690,
                   |                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=77696
     Ever confirmed|0                           |1

--- Comment #5 from Eric Gallager <egallager at gcc dot gnu.org> ---
Confirmed since a bug that this blocks is confirmed.