remote: rename function omit_name_by_refspec

remote: rename function omit_name_by_refspec

Rename the function `omit_name_by_refspec()` to
`refname_matches_negative_refspec_item()` to provide clearer intent.
The previous function name was vague and did not accurately describe its
purpose. By using `refname_matches_negative_refspec_item`, make the
function's purpose more intuitive, clarifying that it checks if a
reference name matches any negative refspec.

Rename function parameters for consistency with existing naming
conventions. Use `refname` instead of `name` to align with terminology
in `refs.h`.

Remove the redundant doc comment since the function name is now
self-explanatory.

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