autodoc: Combine adjacent elements with identical pod

If adjacent items share the same pod, it makes things more compact and
easier to read if they are combined into a single group.

Most instances of this actually happening are when the items all point
to the same external pod for their detailed descriptions.

This saves about 300 lines in the current pod.

autodoc.pl

@@ -2201,6 +2201,27 @@ ($)
         }
 
         if ($section_info && keys $section_info->%*) {
+            my $leader_name;
+            my $leader_pod;
+
+            # To make things even more compact, go through the list, and
+            # combine adjacent elements that have identical pod.
+            for my $next_name (sort dictionary_order keys %$section_info) {
+                my $this_pod = $section_info->{$next_name}{pod};
+
+                # Combine if are the same pod
+                if ($leader_pod && $this_pod && $leader_pod eq $this_pod) {
+                    push $section_info->{$leader_name}{items}->@*,
+                         $section_info->{$next_name}{items}->@*;
+                    delete $section_info->{$next_name};
+                }
+                else {  # Set new pod otherwise
+                    $leader_pod = $this_pod;
+                    $leader_name = $next_name;
+                }
+            }
+
+            # Then, output everything.
             for my $function_name (sort dictionary_order keys %$section_info) {
                 docout($fh, $function_name, $section_info->{$function_name});
             }