Change a link to the web version of the TAP::Parser::Grammar
documentation to link to metacpan.org instead of search.cpan.org.
This is something I added back in commit
20873f45e7 ("t/README:
Document the do's and don'ts of tests", 2010-07-02), at the time
search.cpan.org was the more actively maintained CPAN web-interface,
nowadays that's metacpan.org.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>