[2.3] Examples that points to the DataCollectorListener should be removed.
Removed outdated translations from the official list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.
tweaks for the web server configuration chapter
Fixed minor typos.
Removing extra whitespace
feature #4142 [Cookbook][Configuration] tweaks for the web server configuration chapter (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Cookbook][Configuration] tweaks for the web server configuration chapter

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

Tweaks to #3915 as suggested by @weaverryan.

Commits
-------

93bbd14 tweaks for the web server configuration chapter
Added the schema_filter option to the reference
feature #4150 Added the schema_filter option to the reference (peterrehm)

This PR was submitted for the 2.5 branch but it was merged into the 2.3 branch instead (closes #4150).

Discussion
----------

Added the schema_filter option to the reference

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

Shall the optional setting be added to XML as well? How?
I am unsure if it is actually to which version this relates to the DoctrineBundle.

Relates to doctrine/migrations#101

Commits
-------

20cba4e Added the schema_filter option to the reference
Added custom format page to translation component
Link from introduction section
Small fixes
Cleanups
Fixed version for composer install
Improvements based on comments
Extra improvements based on comments
Fixed wrong indentation
feature #4140 [Cookbook][Logging] document multiple recipients in XML configs (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Cookbook][Logging] document multiple recipients in XML configs

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes (symfony/MonologBundle#91)
| Applies to    | all
| Fixed tickets | #3940, #4135

Commits
-------

37ab23d document multiple recipients in XML configs
bug #4145 Fix documentation for group_sequence_provider (giosh94mhz)

This PR was merged into the 2.3 branch.

Discussion
----------

Fix documentation for group_sequence_provider

The current documentation for `group_sequence_provider` option in the docs is wrong.
It states that the option should be set with:
```YAML
Your\Class\Name:
    group_sequence_provider: ~
    ...
````
But this didn't work.

By looking at the unit test I came up the the right version:
```YAML
Your\Class\Name:
    group_sequence_provider: true
    ...
````

Commits
-------

81cec5d Fix documentation for group_sequence_provider