Markdown.pl: treat '*' in <ol> like last marker

When processing list items, while changes to the list marker style
are allowed for "ol" lists (ignored for "ul" lists), switching
from "ol" to "ul" or vice-versa is not allowed mid-list.

When a numbered/lettered marker is seen while processing a "ul"
list it was simply treated as '*'.  This always produced the
correct result since the actual marker does not matter for "ul"
lists.

However, when a '*', '+', or '-' was seen while processing a
"ol" list it was always treated as a '1.' marker.  This is,
however, incorrect if the list is not using decimal numbering.

Instead treat a "ul" marker encountered during "ol" list
processing as a repeat of the last marker seen.  The lazy
list numbering will kick in and bump it up by one while
retaining the correct list marker style.

The same treatment is also now given to "ol" markers encountered
during "ul" list processing since it's simpler to code that way
even though it doesn't make a difference in output in that case.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>

Markdown.pl

@@ -1490,6 +1490,7 @@ sub _ProcessListItems {
     my $first_marker;
     my $first_marker_type;
     my $first_marker_num;
+    my $last_marker;
     my $fancy;
     my $skipped;
     my $typechanged;
@@ -1515,10 +1516,21 @@ sub _ProcessListItems {
 	    $result .= substr($list_str, $oldpos, $-[0] - $oldpos); # Sort-of $`
 	    $oldpos = $-[0]; # point at start of this entire match
 	}
-	if ($list_marker !~ /$marker_kind/) {
+	if (!defined($first_marker)) {
+	    $first_marker = $last_marker = $list_marker;
+	    $first_marker_type = _GetListMarkerType($list_type, $first_marker);
+	    if ($first_marker_type) {
+		(my $marker_val = $first_marker) =~ s/[.\)]$//;
+		$first_marker_num = _GetMarkerIntegerNum($first_marker_type, $marker_val);
+		$next_num = $first_marker_num;
+		$skipped = 1 if $next_num != 1;
+	    }
+	} elsif ($list_marker !~ /$marker_kind/) {
 	    # Wrong marker kind, "fix up" the marker to a correct "lazy" marker
 	    # But keep the old length in $list_marker_len
-	    $list_marker = $list_type eq "ul" ? "*" : "1.";
+	    $list_marker = $last_marker;
+	} else {
+	    $last_marker = $list_marker;
 	}
 
 	# Now grab the rest of this item's data upto but excluding the next
@@ -1553,16 +1565,6 @@ sub _ProcessListItems {
 	my $checkbox = '';
 	my $incr = '';
 
-	if (!defined($first_marker)) {
-	    $first_marker = $list_marker;
-	    $first_marker_type = _GetListMarkerType($list_type, $first_marker);
-	    if ($first_marker_type) {
-		(my $marker_val = $first_marker) =~ s/[.\)]$//;
-		$first_marker_num = _GetMarkerIntegerNum($first_marker_type, $marker_val);
-		$next_num = $first_marker_num;
-		$skipped = 1 if $next_num != 1;
-	    }
-	}
 	if ($list_type eq "ul" && !$leading_item_space && $item =~ /^\[([ xX])\] +(.*)$/s) {
 	    my $checkmark = lc $1;
 	    $item = $2;