tag: change misleading --list <pattern> documentation

tag: change misleading --list <pattern> documentation

Change the documentation for --list so that it's described as a
toggle, not as an option that takes a <pattern> as an argument.

Junio initially documented this in b867c7c23a ("git-tag: -l to list
tags (usability).", 2006-02-17), but later Jeff King changed "tag" to
accept multiple patterns in 588d0e834b ("tag: accept multiple patterns
for --list", 2011-06-20).

However, documenting this as "-l <pattern>" was never correct, as
these both worked before Jeff's change:

    git tag -l 'v*'
    git tag 'v*' -l

One would expect an option that was documented like that to only
accept:

    git tag --list
    git tag --list 'v*rc*'

And after Jeff's change, one that took multiple patterns:

    git tag --list 'v*rc*' --list '*2.8*'

But since it's actually a toggle all of these work as well, and
produce identical output to the last example above:

    git tag --list 'v*rc*' '*2.8*'
    git tag --list 'v*rc*' '*2.8*' --list --list --list
    git tag --list 'v*rc*' '*2.8*' --list -l --list -l --list

Now the documentation is more in tune with how the "branch" command
describes its --list option since commit cddd127b9a ("branch:
introduce --list option", 2011-08-28).

Change the test suite to assert that these invocations work for the
cases that weren't already being tested for.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>