Replace apostrophe with right single quote to avoid markdown interpre…

…tation as issue 39.

lib/redcarpet/render/gitlab_html.rb

@@ -10,6 +10,11 @@ def initialize(template, options = {})
     super options
   end
 
+  def normal_text(text)
+    return text unless text.present?
+    text.gsub("'", "’")
+  end
+
   def block_code(code, language)
     # New lines are placed to fix an rendering issue
     # with code wrapped inside <h1> tag for next case:

spec/helpers/gitlab_markdown_helper_spec.rb

@@ -535,7 +535,7 @@ def url_helper(image_name)
       project.issues.stub(:where).with(iid: '39').and_return([issue])
 
       actual   = "Yes, it is @#{member.user.username}'s task."
-      expected = /Yes, it is <a.+>@#{member.user.username}<\/a>'s task/
+      expected = /Yes, it is <a.+>@#{member.user.username}<\/a>’s task/
       markdown(actual).should match(expected)
     end
 
@@ -566,7 +566,7 @@ def url_helper(image_name)
 
     it "should leave inline code untouched" do
       markdown("\nDon't use `$#{snippet.id}` here.\n").should ==
-        "<p>Don't use <code>$#{snippet.id}</code> here.</p>\n"
+        "<p>Don’t use <code>$#{snippet.id}</code> here.</p>\n"
     end
 
     it "should leave ref-like autolinks untouched" do