Fix warning generated by VS17.4 related to formattable concept

[dinomight]

In VS17.4, the formattable local variable hides a concept of the same name. This causes a C4459 warning to be triggered. Renaming the local variable fixes the warning.

Fixes #4353

[vitaut]

Please post the full warning.

[dinomight]

Please post the full warning.

Here's the full output with some source paths modified slightly.

1>fmt\base.h(1653,18): error C2220: the following warning is treated as an error
1>fmt\base.h(1653,18): warning C4459: declaration of 'formattable' hides global declaration
1>fmt\base.h(2751,9): message : see declaration of 'fmt::v11::formattable'
1>fmt\base.h(1676,1): message : see reference to function template instantiation 'const Char *fmt::v11::detail::invoke_parse<const uint64_t&,Char>(fmt::v11::parse_context<Char> &)' being compiled
1>        with
1>        [
1>            Char=char
1>        ]
1>fmt\base.h(2703,1): message : see reference to function template instantiation 'fmt::v11::detail::format_string_checker<char,2,0,false>::format_string_checker<const uint64_t&,const uint16_t&>(fmt::v11::basic_string_view<char>,fmt::v11::detail::arg_pack<const uint64_t &,const uint16_t &>)' being compiled
1>source.h(30,1): message : see reference to function template instantiation 'fmt::v11::fstring<const uint64_t &,const uint16_t &>::fstring<41>(const char (&)[41])' being compiled
1>fmt\base.h(1702,20): message : while evaluating constexpr function 'fmt::v11::detail::format_string_checker<char,2,0,false>::on_format_specs'
1>fmt\base.h(1578,33): message : while evaluating constexpr function 'fmt::v11::detail::format_string_checker<char,2,0,false>::on_replacement_field'
1>fmt\base.h(1621,42): message : while evaluating constexpr function 'fmt::v11::detail::parse_replacement_field'
1>fmt\base.h(2708,53): message : while evaluating constexpr function 'fmt::v11::detail::parse_format_string'

[vitaut]

Thanks for the PR but since doesn't look like an improvement and the false positive appears to be fixed in newer version of MSVC, I don't think we need to do anything.