md_is_setext_underline: On succeess, update p_end to save caller some work.
diff --git a/md4c/md4c.c b/md4c/md4c.c
index 927a046..5618450 100644
--- a/md4c/md4c.c
+++ b/md4c/md4c.c
@@ -3931,6 +3931,7 @@ md_is_setext_underline(MD_CTX* ctx, OFF beg, OFF* p_end, unsigned* p_level)
return FALSE;
*p_level = (CH(beg) == _T('=') ? 1 : 2);
+ *p_end = off;
return TRUE;
}