c++: Improve printing of pointers-to-members [PR97406, PR85901]

c++: Improve printing of pointers-to-members [PR97406, PR85901]

This PR points out that when printing the parameter mapping for a
pointer-to-member-function, the output was truncated:

  [with T = void (X::*]

Fixed by printing the abstract declarator for pointers-to-members in
cxx_pretty_printer::type_id.  So now we print:

  [with T = void (X::*)()]

But when I tried a pointer-to-data-member, I got

  [with T = ‘offset_type’ not supported by simple_type_specifier)‘offset_type’ not supported by direct_abstract_declarator]

so had to fix that too so that we now print:

  [with T = int X::*]

or

  [with T = int (X::*)[5]]

when the type is an array type.  Which is what PR85901 was about.

gcc/cp/ChangeLog:

	PR c++/97406
	PR c++/85901
	* cxx-pretty-print.c (pp_cxx_type_specifier_seq): Handle OFFSET_TYPE.
	(cxx_pretty_printer::abstract_declarator): Fix the printing of ')'.
	(cxx_pretty_printer::direct_abstract_declarator): Handle OFFSET_TYPE.
	(cxx_pretty_printer::type_id): Likewise.  Print the abstract declarator
	for pointers-to-members.

gcc/testsuite/ChangeLog:

	PR c++/97406
	PR c++/85901
	* g++.dg/diagnostic/ptrtomem1.C: New test.
	* g++.dg/diagnostic/ptrtomem2.C: New test.