Enhance test convertible_to_path_and_strings for all char types

[Flamefire]

This extends the test in fbd23ee to include all possible Source types accepted by is_convertible_to_path_source

See :

filesystem/include/boost/filesystem/detail/path_traits.hpp

Lines 562 to 571 in fbd23ee

	yes_type check_convertible(const char*);
	yes_type check_convertible(const wchar_t*);
	yes_type check_convertible(std::string const&);
	yes_type check_convertible(std::wstring const&);
	yes_type check_convertible(boost::container::basic_string< char, std::char_traits< char >, void > const&);
	yes_type check_convertible(boost::container::basic_string< wchar_t, std::char_traits< wchar_t >, void > const&);
	yes_type check_convertible(boost::basic_string_view< char, std::char_traits< char > > const&);
	yes_type check_convertible(boost::basic_string_view< wchar_t, std::char_traits< wchar_t > > const&);
	no_type check_convertible(std::nullptr_t);
	no_type check_convertible(...);

[Lastique]

This has no effect. The point of the test is to have an ambiguous conversion to a Source type. It doesn't matter which of the candidate types are supported by the original type.

[Flamefire]

This has no effect. The point of the test is to have an ambiguous conversion to a Source type. It doesn't matter which of the candidate types are supported by the original type.

With this enhancement I just want to make sure the ambiguity resolution is not dependent on e.g. the native char type or any of the other possible string-likes.
The (test) code is very simple and it fits the class name convertible_to_path_and_strings, so what does it cost to include it to avoid future regressions?

[Lastique]

With this enhancement I just want to make sure the ambiguity resolution is not dependent on e.g. the native char type or any of the other possible string-likes.

path will always support constructors/operations taking native strings, so the existing conversion operators are enough to introduce ambiguity. I don't see the point of adding more operators, it doesn't add anything.