Merge branch '5.0'

* 5.0: (36 commits)
  Add test for tagged iterator with numeric index
  Fix container lint command when a synthetic service is used in combination with the expression language
  Fix Travis script
  [Validator][Range] Fix typos
  [SecurityBundle] Minor fix in LDAP config tree builder
  [HttpClient] fix requests to hosts that idn_to_ascii() cannot handle
  Revert "minor #35559 [FrameworkBundle] remove mention of the old Controller class (nicolas-grekas)"
  [FrameworkBundle] remove redundant PHPDoc in console Descriptor and subclass
  [Mime] remove phpdoc mentioning Utf8AddressEncoder
  Add missing phpdoc
  Remove int return type from FlattenException::getCode
  [Yaml] fix dumping strings containing CRs
  [DI] Fix XmlFileLoader bad error message
  [Form] Handle false as empty value on expanded choices
  [Messenger] Add ext-redis min version req to tests
  Tweak message
  improve PlaintextPasswordEncoder docBlock summary
  [Validator] Add two missing translations for the Arabic (ar) locale
  Use some PHP 5.4 constants unconditionally
  Add new packages on the link script
  ...

Author: nicolas-grekas

Encoder/PlaintextPasswordEncoder.php

@@ -14,7 +14,9 @@
 use Symfony\Component\Security\Core\Exception\BadCredentialsException;
 
 /**
- * PlaintextPasswordEncoder does not do any encoding.
+ * PlaintextPasswordEncoder does not do any encoding but is useful in testing environments.
+ *
+ * As this encoder is not cryptographically secure, usage of it in production environments is discouraged.
  *
  * @author Fabien Potencier <[email protected]>
  */