Fixed #16071 -- Added note to fix_ampersands documentation about its…

Fixed #16071 -- Added note to fix_ampersands documentation about its limitations. Many thanks to jerry and Julien Phalip.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16431 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/ref/templates/builtins.txt

@@ -1510,6 +1510,14 @@ For example::
 
 If ``value`` is ``Tom & Jerry``, the output will be ``Tom & Jerry``.
 
+However, ampersands used in named entities and numeric character references
+will not be replaced. For example, if ``value`` is ``Café``, the output
+will *not* be ``Caf&eacute&`` but remain ``Café``. This means that
+in some edge cases, such as acronyms followed by semicolons, this filter will
+not replace ampersands that need replacing. For example, if ``value`` is
+``Contact the R&D;``, the output will remain unchanged because ``&D;``
+resembles a named entity.
+
 .. templatefilter:: floatformat
 
 floatformat