Remove git.io shortlinks from repo (#9045)

Merge pull request 9045

lib/jekyll/commands/doctor.rb

@@ -157,7 +157,7 @@ module Jekyll
           Addressable::URI.parse(url)
           true
         # Addressable::URI#parse only raises a TypeError
-        # https://git.io/vFfbx
+        # https://github.com/sporkmonger/addressable/blob/0a0e96acb17225f9b1c9cab0bad332b448934c9a/lib/addressable/uri.rb#L103
         rescue TypeError
           Jekyll.logger.warn "Warning:", "The site URL does not seem to be valid, "\
               "check the value of `url` in your config file."

lib/jekyll/filters.rb

@@ -478,7 +478,7 @@ module Jekyll
     end
 
     # -----------   The following set of code was *adapted* from Liquid::If
-    # -----------   ref: https://git.io/vp6K6
+    # -----------   ref: https://github.com/Shopify/liquid/blob/ffb0ace30315bbcf3548a0383fab531452060ae8/lib/liquid/tags/if.rb#L84-L107
 
     # Parse a string to a Liquid Condition
     def parse_condition(exp)