pathspec: always show mnemonic and name in unsupported_magic
For better clarity, always show the mnemonic and name of the unsupported
magic being used. This lets users have a more clear understanding of
what magic feature isn't supported. And if they supplied a mnemonic,
the user will be told what its corresponding name is which will allow
them to more easily search the man pages for that magic type.
This also avoids passing an extra parameter around the pathspec
initialization code.
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>