`std::formatter` specialization

[rdong8]

Please provide a std::formatter specialization similar to the one std::stacktrace provides:

https://godbolt.org/z/x3zKn6vfn

terminate called after throwing an instance of 'RuntimeError'
  what():  Encountered error code: 139
   0# RuntimeError::RuntimeError<int>(std::basic_format_string<char, std::type_identity<int>::type>, int&&) at /app/example.cpp:16
   1#  h() at /app/example.cpp:23
   2#  g() at /app/example.cpp:28
   3#  f() at /app/example.cpp:33
   4# main at /app/example.cpp:38
   5#      at :0
   6# __libc_start_main at :0
   7# _start at :0
   8#