Merge branch '1.x' into 2.x

* 1.x:
  tweaked docs
  Add information for when `filter` filter was added in 2.x branch
  tweaked docs
  doc(filter): add example of `filter` without `for` use

doc/filters/filter.rst

@@ -2,7 +2,7 @@
 =========
 
 .. versionadded:: 1.41
-    The ``filter`` filter was added in Twig 1.41.
+    The ``filter`` filter was added in Twig 1.41 and 2.10.
 
 The ``filter`` filter filters elements of a sequence or a mapping using an arrow
 function. The arrow function receives the value of the sequence or mapping:
@@ -11,11 +11,22 @@ function. The arrow function receives the value of the sequence or mapping:
 
     {% set sizes = [34, 36, 38, 40, 42] %}
 
+    {{ sizes|filter(v => v > 38)|join(', ') }}
+    {# output 40, 42 #}
+
+Combined with the ``for`` tag, it allows to filter the itemss to iterate over:
+
+.. code-block:: twig
+
     {% for v in sizes|filter(v => v > 38) -%}
         {{ v }}
     {% endfor %}
     {# output 40 42 #}
 
+It also works with mappings:
+
+.. code-block:: twig
+
     {% set sizes = {
         xs: 34,
         s:  36,