removed obsolete note from the doc

doc/templates.rst

@@ -950,13 +950,6 @@ Arrays and hashes can be nested:
 
     {% set foo = [1, {"foo": "bar"}] %}
 
-.. caution::
-
-    When defining nested hashes, be careful to put at least one whitespace
-    between the two closing curly braces like in this example: ``{ 'foo: {
-    'bar': 'foobar' } }``. If not, Twig will interpret ``}}`` as the end of
-    the expression.
-
 Math
 ~~~~