describe: teach --match to accept multiple patterns

describe: teach --match to accept multiple patterns

Teach `--match` to be accepted multiple times, accumulating a list of
patterns to match into a string list. Each pattern is inclusive, such
that a tag need only match one of the provided patterns to be
considered for matching.

This extension is useful as it enables more flexibility in what tags
match, and may avoid the need to run the describe command multiple
times to get the same result.

Add tests and update the documentation for this change.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>