At least mark the URL to the Packages essay using \url.

Doc/ref/ref6.tex

@@ -521,7 +521,7 @@ generally a subdirectory of a directory on \code{sys.path} that has a
 file \file{__init__.py}.\ttindex{__init__.py}
 %
 [XXX Can't be bothered to spell this out right now; see the URL
-http://www.python.org/doc/essays/packages.html for more details, also
+\url{http://www.python.org/doc/essays/packages.html} for more details, also
 about how the module search works from inside a package.]
 
 [XXX Also should mention __import__().]