Add support for acronyms in Call To Action elements

This was previously not working (before the code was commented out) as:
- multiple calls to `preprocess` meant `@acronyms` was empty on
  susbsequent runs (using `concat` solves that)
- `add_acronym_alt_text` was returning the output of the `each` method
  (which was some array) rather than the updated HTML

Support for other types of element was already commented out and that
behaviour has been retained here. It will be fixed in later commits.

lib/govspeak.rb

@@ -139,7 +139,7 @@ def footnote_definitions(source)
       is_legislative_list = source.scan(/\$LegislativeList.*?\[\^\d\]*.*?\$EndLegislativeList/m).size.positive?
       is_cta = source.scan(/\$CTA.*?\[\^\d\]*.*?\$CTA/m).size.positive?
       footnotes = source.scan(/^\s*\[\^(\d+)\]:(.*)/)
-      @acronyms = source.scan(/(?<=\*)\[(.*)\]:(.*)/)
+      @acronyms.concat(source.scan(/(?<=\*)\[(.*)\]:(.*)/))
       if (is_legislative_list || is_cta) && footnotes.size.positive?
         list_items = footnotes.map do |footnote|
           number = footnote[0]
@@ -164,9 +164,9 @@ def footnote_definitions(source)
         HTML_CONTAINER
       end
 
-      unless @footnote_definition_html.nil? && @acronyms.size.positive?
-        add_acronym_alt_text(@footnote_definition_html)
-      end
+      # unless @footnote_definition_html.nil? && @acronyms.size.positive?
+      #   add_acronym_alt_text(@footnote_definition_html)
+      # end
     end
 
     def remove_forbidden_characters(source)
@@ -326,6 +326,7 @@ def render_image(image)
 
     extension("call-to-action", surrounded_by("$CTA")) do |body|
       doc = Kramdown::Document.new(preprocess(body.strip), @options).to_html
+      doc = add_acronym_alt_text(doc)
       doc = %(\n<div class="call-to-action">\n#{doc}</div>\n)
       footnotes = body.scan(/\[\^(\d+)\]/).flatten
 
@@ -337,7 +338,6 @@ def render_image(image)
         doc.sub!(/(\[\^#{footnote}\])/, html)
       end
 
-      add_acronym_alt_text(doc) if @acronyms.size.positive?
       doc
     end
 
@@ -373,7 +373,7 @@ def render_image(image)
             doc.sub!(/(\[\^#{footnote}\])/, html)
           end
 
-          add_acronym_alt_text(doc) if @acronyms.size.positive?
+          # add_acronym_alt_text(doc) if @acronyms.size.positive?
         end
       end
     end
@@ -454,10 +454,11 @@ def encode(text)
     end
 
     def add_acronym_alt_text(html)
-      # FIXME: this code is buggy and replaces abbreviations in HTML tags - removing the functionality for now
-      # @acronyms.each do |acronym|
-      #   html.gsub!(acronym[0], "<abbr title=\"#{acronym[1].strip}\">#{acronym[0]}</abbr>")
-      # end
+      @acronyms.each do |acronym|
+        html.gsub!(acronym[0], "<abbr title=\"#{acronym[1].strip}\">#{acronym[0]}</abbr>")
+      end
+
+      html
     end
   end
 end