Documentation/Makefile: add missing xsl dependencies for manpages

These stylesheets very rarely change, but when they do, it really helps
if the manpages depend on them. We're casting the net a bit too wide
here, since we'll only ever use a subset of the stylesheets, but since
these files change so rarely, that should be ok. It's better than
missing a dependency.

Observe that manpage-base-url.xsl is a generated file, so we need to
list it explicitly, besides the `wildcard` expression we're adding here.

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

Documentation/Makefile

@@ -347,7 +347,7 @@ $(OBSOLETE_HTML): %.html : %.txto asciidoc.conf
 manpage-base-url.xsl: manpage-base-url.xsl.in
 	$(QUIET_GEN)sed "s|@@MAN_BASE_URL@@|$(MAN_BASE_URL)|" $< > $@
 
-%.1 %.5 %.7 : %.xml manpage-base-url.xsl
+%.1 %.5 %.7 : %.xml manpage-base-url.xsl $(wildcard manpage*.xsl)
 	$(QUIET_XMLTO)$(RM) $@ && \
 	$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<