gistfile1.txt

Original
#<Asciidoctor::ListItem@47313569818400 {list_context: :ulist, text: "<<worklist,Worklist>>", blocks: 0}>

new_block
#<Asciidoctor::ListItem@47313570547660 {list_context: :ulist, text: "{{<a href=\"#worklist\">Worklist</a> | localize}}", blocks: 0}>

Desired
#<Asciidoctor::ListItem@47313570547660 {list_context: :ulist, text: "{{<<worklist,Worklist>> | localize}}", blocks: 0}>

wrap-text-with-filter.rb

#!/usr/bin/env ruby

require 'asciidoctor'
require 'asciidoctor/extensions'

class AngularLocalizeWrapperTreeprocessor < Asciidoctor::Extensions::Treeprocessor
    def process document
        return unless document.blocks?
        process_blocks document
        nil
    end

    def process_blocks node
        node.blocks.each_with_index do |block, i|
          class_name = block.class.name.split('::').last
          case class_name
          when 'Block'
            block.lines = block.lines.map do |line|
              line = wrap_text(line)
            end
            node.blocks[i] = block
          when 'ListItem'
            # Apperantly cannot assign block.text a new value
            puts block
            new_block = Asciidoctor::ListItem.new(block.parent, wrap_text(block.text))
            puts new_block
            node.blocks[i] = new_block
          else
            puts %(Unhandled class: #{class_name})
          end

          process_blocks block if block.respond_to?('blocks')
        end
    end

    def wrap_text text
      %({{#{text} | localize}}) 
    end
end

Asciidoctor::Extensions.register do 
    treeprocessor AngularLocalizeWrapperTreeprocessor
end

Asciidoctor.convert_file 'documentation/manual.adoc', :safe => :unsafe