[2.3] Examples that points to the DataCollectorListener should be removed.
[Security] Added remote_user firewall info and documentation for pre authenticated firewalls
[Reference][Configuration] Removed version added for remote_user
rebased using x509 pr, added remote_user pre authenticated part
fix missing backtick, rephrased bottom note
fixes missing backtick
Removed outdated translations from the official list
Fix documentation for group_sequence_provider
document multiple recipients in XML configs

Adds an example on how to configure multiple recipients in Monolog
for sending log entries as e-mails.
add missing Monolog handler type in XML config
fix from suffix to prefix
[Reference] fix namespace in Expression constraint
bug #4147 [Cookbook][Logging] add missing Monolog handler type in XML config (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Cookbook][Logging] add missing Monolog handler type in XML config

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Omitting the type of a handler leads to an error:

> Symfony\Component\Config\Definition\Exception\InvalidConfigurationException: The child node "type" at path "monolog.handlers.swift" must be configured.

Commits
-------

dc33b0c add missing Monolog handler type in XML config
Added hint about attaching the expression constraint to a form field
feature #4086 [Reference][Constraints] Added hint about attaching the expression constraint to a form field (peterrehm)

This PR was submitted for the master branch but it was merged into the 2.4 branch instead (closes #4086).

Discussion
----------

[Reference][Constraints] Added hint about attaching the expression constraint to a form field

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.4
| Fixed tickets | -

As per my discussion with @webmozart a while ago on twitter https://twitter.com/peterrehm/status/434350363940904960 I am now providing the hint about the possibility to add a expression constraint to a form field.

Commits
-------

3023dc3 Added hint about attaching the expression constraint to a form field
minor #4136 [Reference] fix from suffix to prefix (xabbuh)

This PR was merged into the master branch.

Discussion
----------

[Reference] fix from suffix to prefix

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.6+
| Fixed tickets |

As @Tobion said in #3895 and like the Wikipedia article describes, the handling of *prefixes* (not suffixes) was introduced.

Commits
-------

d185f40 fix from suffix to prefix
Merge branch '2.3' into 2.4

* 2.3:
  add missing Monolog handler type in XML config
Merge branch '2.4' into 2.5

* 2.4:
  Added hint about attaching the expression constraint to a form field
  add missing Monolog handler type in XML config
Merge branch '2.5'

* 2.5:
  Added hint about attaching the expression constraint to a form field
  add missing Monolog handler type in XML config
tweaks for the web server configuration chapter