Merge branch '4.3' into 4.4

* 4.3:
  Minor fixes

Author: javiereguiluz

reference/configuration/framework.rst

@@ -2813,7 +2813,7 @@ A list of lock stores to be created by the framework extension.
 
     .. code-block:: yaml
 
-        # config/packages/lock.yml
+        # config/packages/lock.yaml
         framework:
             # these are all the supported lock stores
             lock: ~

reference/forms/types/collection.rst

@@ -184,7 +184,7 @@ And update the template as follows:
         <ul id="email-fields-list"
             data-prototype="{{ form_widget(form.emails.vars.prototype)|e }}"
             data-widget-tags="{{ '<li></li>'|e }}"
-            data-widget-counter="{{ form.children|length }}">
+            data-widget-counter="{{ form.emails|length }}">
         {% for emailField in form.emails %}
             <li>
                 {{ form_errors(emailField) }}