[Bug c++/84269] More suggestions for missing #include

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84269

--- Comment #8 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
From PR 84896:

gcc 8 currently emits the following for:

  std::pair<int, int> foo;

error: 'pair' in namespace 'std' does not name a template type
 std::pair<int, int> foo;
      ^~~~

We ought to suggest including <utility> for this, and probably various other
stdlib templates.