remote: rename query_refspecs functions

remote: rename query_refspecs functions

Rename functions related to handling refspecs in preparation for their
move from `remote.c` to `refspec.c`. Update their names to better
reflect their intent:

    - `query_refspecs()` -> `refspec_find_match()` for clarity, as it
      finds a single matching refspec.

    - `query_refspecs_multiple()` -> `refspec_find_all_matches()` to
      better reflect that it collects all matching refspecs instead of
      returning just the first match.

    - `query_matches_negative_refspec()` ->
      `refspec_find_negative_match()` for consistency with the
      updated naming convention, even though this static function
      didn't strictly require renaming.

Signed-off-by: Meet Soni <meetsoni3017@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>