CSRF warning docs on Request::enableHttpMethodParameterOverride()

[HttpFoundation] fixed the docs so that it gives some explanation about how you are vulnerable to CSRF when you enable the httpMethodeParameterOverride
improve error message for multiple documents

The YAML parser doesn't support multiple documents. This pull requests
improves the error message when the parser detects multiple YAML
documents.
bug #12370 [Yaml] improve error message for multiple documents (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Yaml] improve error message for multiple documents

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

The YAML parser doesn't support multiple documents. This pull requests
improves the error message when the parser detects multiple YAML
documents.

see also #11840

Commits
-------

c77fdcb improve error message for multiple documents
minor #12168 [HttpFoundation] CSRF warning docs on Request::enableHttpMethodParameterOverride() (Kristof Van Cauwenbergh)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] CSRF warning docs on Request::enableHttpMethodParameterOverride()

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12043
| License       | MIT
| Doc PR        | /

Since I wanted to understand this issue I did some research and altered the comment block. Is this a clear enough explanation or does it need more?

Commits
-------

deb70ab CSRF warning docs on Request::enableHttpMethodParameterOverride()
added missing files
TwigExtractor tests require the Finder component
minor #12398 [TwigBridge] TwigExtractor tests require the Finder component (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[TwigBridge] TwigExtractor tests require the Finder component

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

The tests for the `TwigExtractor`(as introduced in #12377) require the Finder component to be run properly.

Commits
-------

8fc3e03 TwigExtractor tests require the Finder component
Fixed case for empty folder
bug #12436 [Filesystem] Fixed case for empty folder (yosmanyga)

This PR was merged into the 2.3 branch.

Discussion
----------

[Filesystem] Fixed case for empty folder

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

The mirror function should work with an empty folder as source. It should create an empty folder on target path.

Commits
-------

5321741 Fixed case for empty folder
[DependencyInjection] inlined factory not referenced
bug #12393 [DependencyInjection] inlined factory not referenced (boekkooi)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12393).

Discussion
----------

[DependencyInjection] inlined factory not referenced

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

While working with the DI I encountered a `You have requested a non-existent service "xxxxx"` exception.
Research it seems that a private reference was inlined but the private factory that was also referencing to the service was ignored.

A example of the problem:
```XML
        <service id="manager"
                 class="\stdClass"
                 factory-method="getX"
                 factory-service="factory"
                 public="false">
            <argument>X</argument>
        </service>
        <service id="repository"
                 class="\stdClass"
                 factory-method="getRepository"
                 factory-service="manager"
                 public="false">
            <argument>X</argument>
        </service>
        <service id="storage" class="\stdClass" public="false">
            <argument type="service" id="manager"/>
            <argument type="service" id="repository"/>
        </service>
```

What happens before the patch:
1. repository get's inlined
2. manager get's inlined for the first argument
3. manager get's removed since there was no reference.

After the first commit the following will happen:
1. repository get's inlined
2. manager get's inlined for the first argument
3. manager will not be removed since the inlined repository still references manager

This introduced a smell since InlineServiceDefinitionsPass was still inlining the manager for the first argument.

To fix this I have chosen that not inline factories if they are used more then once by the same definition.

So after the second commit the following will happen:
1. repository get's inlined

Personally I feel that the InlineServiceDefinitionsPass patch isn't the best possible one but that a different fix would probably mean breaking BC so it's probably a good idea to look at this for Symfony 3.0.

Commits
-------

7816a98 [DependencyInjection] inlined factory not referenced
[Translations] Added missing Hebrew language trans-unit sources
minor #12450 [Translations] Added missing Hebrew language trans-unit sources (excelwebzone)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12450).

Discussion
----------

[Translations] Added missing Hebrew language trans-unit sources

[Form] [Validator] [Translations] added missing files
[Security][Translations] added missing files

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        | no

Commits
-------

918b16b [Translations] Added missing Hebrew language trans-unit sources
fixed typo
minor #12449 fixed typo (ojhaujjwal)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12449).

Discussion
----------

fixed typo

Commits
-------

a7c2a9a fixed typo
Add machine readable events
minor #12299 Add machine readable events (dawehner)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12299).

Discussion
----------

Add machine readable events

As discussed in [#11878] it would be great to have some simple machine readable way to find events

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11878
| License       | MIT

Commits
-------

ace9a22 Add machine readable events
Update filesystem readme.md to include exists method
minor #12468 Update filesystem readme.md to include exists method (ericduran)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12468).

Discussion
----------

Update filesystem readme.md to include exists method

Read the contributing docs, I don't think I missed anything but to be fair I went through it pretty fast :-/

Commits
-------

16c1b66 Update filesystem readme.md to include exists method
don't override internal PHP constants