Revert "docbook: remove equivalent case."

We still need the "length == 2" behavior.

This reverts commit 622b17a475.

Change-Id: Id3b7ed9231f3fefeeac5fb910b792139c4844ec8
Reviewed-on: https://code.wireshark.org/review/28484
Reviewed-by: Gerald Combs <gerald@wireshark.org>

docbook/asciidoctor-macros/commaize-block/extension.rb

@@ -33,6 +33,8 @@ class CommaizeBlock < Extensions::BlockProcessor
 
     if lines.length < 2
       create_paragraph parent, lines, attrs
+    elsif lines.length == 2
+      create_paragraph parent, lines.join(" and "), attrs
     else
       commaized = lines[0..-2].join(", ")
       commaized << ", and " + lines[-1]