[book] [validation] fixed minor typos
[book] [testing] fixed the path of the phpunit.xml file

Sometimes is referenced as phpunit.xml and other times as
app/phpunit.xml I think that we should always use the explicit
app/phpunit.xml path, except when explaining the phpunit.xml
file in general.
[book] [controller] fixed the code of a session sample code

This code was updated in the past to use the $request controller
injection and the resulting code was a bit confusing. When you get
the attribute set by another controller, it's better to use a
different attribute name, to make it clear that it wasn't set at
this controller.
Added a note about inlined private services
Emphasized the fact that this only applies when the private service is used as argument for a single service
added the title of a cross reference
minor #3727 Added a note about inlined private services (javiereguiluz)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #3727).

Discussion
----------

Added a note about inlined private services

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | 2.3+
| Fixed tickets | -

When you define private services that are used just as arguments for another service, Symfon2 doesn't define them as services, but inlines them in the other service definition. This slightly improves the performance of the container, but it's confusing for Symfony beginners because the private services aren't displayed by the `container:debug` command even when using the `--show-private` option:

```
$ php app/console container:debug --show-private
```

Commits
-------

15a7be0 [book] [service_container] added the title of a cross reference
835b52f Emphasized the fact that this only applies when the private service is used as argument for a single service
04cb9d4 Added a note about inlined private services
Update routing.rst. Explain using url() v. path().
minor #3732 Update routing.rst. Explain using url() v. path(). (ackerman)

This PR was submitted for the 2.4 branch but it was merged into the 2.3 branch instead (closes #3732).

Discussion
----------

Update routing.rst. Explain using url() v. path().

The original documentation seemed to imply that, when generating absolute URLs from a template, the argument TRUE should be supplied to the url() method. This change explains that in Twig, one uses the url() method to generate an absolute URL.

Commits
-------

6eac303 Update routing.rst. Explain using url() v. path().
minor #3733 [book] [validation] fixed minor typos (javiereguiluz)

This PR was merged into the 2.3 branch.

Discussion
----------

[book] [validation] fixed minor typos

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3+
| Fixed tickets | -

Commits
-------

693ba24 [book] [validation] fixed minor typos
bug #3734 [book] [testing] fixed the path of the phpunit.xml file (javiereguiluz)

This PR was merged into the 2.3 branch.

Discussion
----------

[book] [testing] fixed the path of the phpunit.xml file

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3+
| Fixed tickets | -

Sometimes is referenced as phpunit.xml and other times as
app/phpunit.xml I think that we should always use the explicit
app/phpunit.xml path, except when explaining the phpunit.xml
file in general.

Commits
-------

a1f5cd6 [book] [testing] fixed the path of the phpunit.xml file
minor #3735 [book] [controller] fixed the code of a session sample code (javiereguiluz)

This PR was merged into the 2.3 branch.

Discussion
----------

[book] [controller] fixed the code of a session sample code

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3+
| Fixed tickets | -

This code was updated in the past to use the $request controller
injection and the resulting code was a bit confusing. When you get
the attribute set by another controller, it's better to use a
different attribute name, to make it clear that it wasn't set at
this controller.

Commits
-------

9da7f9b [book] [controller] fixed the code of a session sample code
Merge branch '2.3' into 2.4
Merge branch '2.4'