This PR was submitted for the 4.1 branch but it was merged into the 2.8 branch instead (closes #10200).

Discussion
----------

action_method is missing $task variable

It's not clear from the docs, but user has to first create the `$task` variable.

In the second example bellow it's more clear thanks to `// ...`.

This makes it a bit more explicit here as well.

Commits
-------

5ada0ef action_method is missing $task variable

* 2.8:
  {% if label is not same as(false) and required %}
  Shorten ternary operator
  Fix wrong usage in custom authenticator checking if password is invalid
  update hardcoded 5.1 version link
  Add undocumented sortByAccessedTime, sortByChangedTime and sortByModifiedTime methods in finder component
  Update bugs.rst
  [#10200] remove trailing spaces
  action_method is missing $task variable
  Fix bad link

* 3.4:
  {% if label is not same as(false) and required %}
  Update service_container.rst
  Shorten ternary operator
  Fix wrong usage in custom authenticator checking if password is invalid
  [Process] Fix typo in Process object initialization
  update hardcoded 5.1 version link
  Add undocumented sortByAccessedTime, sortByChangedTime and sortByModifiedTime methods in finder component
  Update bugs.rst
  [#10200] remove trailing spaces
  action_method is missing $task variable
  Fix bad link

* 4.1:
  {% if label is not same as(false) and required %}
  minor language tweak
  Update service_container.rst
  Fix wrong exception used in custom authentication provider example
  [Console] Replace useless usage of ContainerAwareCommand
  Shorten ternary operator
  Fix wrong usage in custom authenticator checking if password is invalid
  [Process] Fix typo in Process object initialization
  update hardcoded 5.1 version link
  Explain dump server usage outside of Symfony
  Add undocumented sortByAccessedTime, sortByChangedTime and sortByModifiedTime methods in finder component
  Update bugs.rst
  [#10200] remove trailing spaces
  action_method is missing $task variable
  [#10177] fix markup
  Clarifying when you need to or don't need to install the server bundle
  Fix bad link
  Update setup.rst
  Also requiring annotations so they can be used

This reverts commit 95dc4ca.