Support the GNU-specific syntax ".IP \\[bu]" for bullet lists in man(7)

pages that Alejandro Colomar recommends in the "Lists" subsection of
https://man7.org/linux/man-pages/man7/man-pages.7.html#STYLE_GUIDE .

For example, this will improve HTML formatting of the first list in
the subsection "Feature test macros understood by glibc" on the page
https://manpages.debian.org/bookworm/manpages/ftm.7.en.html .

Issue reported by Alejandro Colomar <alx at kernel dot org>.

1 files changed, 4 insertions, 2 deletions

diff --git a/man_html.c b/man_html.c
index 630e2856..3e333e6a 100644
--- a/man_html.c
+++ b/man_html.c
@@ -433,10 +433,12 @@ list_continues(const struct roff_node *n1, const struct roff_node *n2)
 	s2 = n2 == NULL ? "" : n2->string;
 	c1 = strcmp(s1, "*") == 0 ? '*' :
 	     strcmp(s1, "\\-") == 0 ? '-' :
-	     strcmp(s1, "\\(bu") == 0 ? 'b' : ' ';
+	     strcmp(s1, "\\(bu") == 0 ? 'b' :
+	     strcmp(s1, "\\[bu]") == 0 ? 'b' : ' ';
 	c2 = strcmp(s2, "*") == 0 ? '*' :
 	     strcmp(s2, "\\-") == 0 ? '-' :
-	     strcmp(s2, "\\(bu") == 0 ? 'b' : ' ';
+	     strcmp(s2, "\\(bu") == 0 ? 'b' :
+	     strcmp(s2, "\\[bu]") == 0 ? 'b' : ' ';
 	return c1 != c2 ? '\0' : c1 == 'b' ? '*' : c1;
 }