FIX: unescape emoji in pretty title

This makes emoji in title consistent, it is later escaped back when needed

app/models/emoji.rb

@@ -146,6 +146,16 @@ class Emoji
     @unicode_replacements
   end
 
+  def self.unicode_unescape(string)
+    string.each_char.map do |c|
+      if str = unicode_replacements[c]
+        ":#{str}:"
+      else
+        c
+      end
+    end.join
+  end
+
   def self.lookup_unicode(name)
     @reverse_map ||= begin
       map = {}

app/models/topic.rb

@@ -295,7 +295,7 @@ class Topic < ActiveRecord::Base
   def self.fancy_title(title)
     escaped = ERB::Util.html_escape(title)
     return unless escaped
-    HtmlPrettify.render(escaped)
+    Emoji.unicode_unescape(HtmlPrettify.render(escaped))
   end
 
   def fancy_title

spec/models/topic_spec.rb

@@ -257,11 +257,16 @@ describe Topic do
     let(:topic_bold) { build_topic_with_title("Topic with <b>bold</b> text in its title" ) }
     let(:topic_image) { build_topic_with_title("Topic with <img src='something'> image in its title" ) }
     let(:topic_script) { build_topic_with_title("Topic with <script>alert('title')</script> script in its title" ) }
+    let(:topic_emoji) { build_topic_with_title("I 💖 candy alot") }
 
     it "escapes script contents" do
       expect(topic_script.fancy_title).to eq("Topic with &lt;script&gt;alert(&lsquo;title&rsquo;)&lt;/script&gt; script in its title")
     end
 
+    it "expands emojis" do
+      expect(topic_emoji.fancy_title).to eq("I :sparkling_heart: candy alot")
+    end
+
     it "escapes bold contents" do
       expect(topic_bold.fancy_title).to eq("Topic with &lt;b&gt;bold&lt;/b&gt; text in its title")
     end