[Bug libstdc++/67440] pretty-printing of a const set<foo> fails

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67440

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think this should be str(typ.unqualified()) otherwise it doesn't work on GDB
7.6:

Python Exception <type 'exceptions.AttributeError'> 'gdb.Type' object has no
attribute 'name'