asciidoctor-extensions: fix spurious space after linkgit

asciidoctor-extensions: fix spurious space after linkgit

When we render, e.g., "linkgit:gitglossary[7]." with Asciidoctor, we get
"gitglossary(7) ." with a space between the linkgit macro expansion and
the punctuation. We can fix this by dropping the trailing newline after
we've turned `linkgit:foo[bar]` into `<citerefentry>..</citerefentry>`.

The diff produced by `USE_ASCIIDOCTOR=Yes ./doc-diff HEAD^ HEAD` is
almost 6000 lines large and shows how this fixes "git-foo(x) ,", "(see
git-bar(y) )" and so on. One might wonder whether this also turns, e.g.,
"see linkgit:foo[1] for more" into "see foo(1)for more", but no. We get
"...</citerefentry> for more" in the XML, see, e.g., git-am.xml, so the
space ends up in git-am.1 just fine. The same is true for the HTML output.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>