Rearrange article id parsing to be more reliable

The article ID parser looks for a string at the end of a URL path with
a bunch of hex digits. But it also has to handle user, tag, and search
URLs.

* /@ba5eba11
* /tag/0ddba11
* /search?q=ba5eba11

Some URLs are encoded as params. The parser used to look at the result
of the path first, then the params. But paths that ended in
`global-identity-2` messed that up because `2` is a hex digit at the
end of the path. This changes the logic to parse params first and paths
second which gets around this.

src/classes/article_id_parser.cr

@@ -10,7 +10,7 @@ class ArticleIdParser
   def parse(request : HTTP::Request) : Maybe
     from_params = post_id_from_params(request.query_params)
     from_path = post_id_from_path(request.path)
-    from_path.or(from_params)
+    from_params.or(from_path)
   end
 
   private def post_id_from_path(request_path : String)