fix ContainerAwareEventDispatcher definition
link translation DIC tags to components section

The `translation.loader` and `translation.dumper` DIC tags link to the
respective sections in the Translation component documentation.
Remove redundant references to trusting HttpCache
feature #4239 Remove redundant references to trusting HttpCache (thewilkybarkid)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #4239).

Discussion
----------

Remove redundant references to trusting HttpCache

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

Removes references to making `HttpCache` a trusted proxy as https://github.com/symfony/symfony/pull/11937 would cause it to be handled automatically.

Alternatively it could be reworded, but I'm not sure it's useful to say that this happens (since it was a bit odd to have to configure Symfony to let one part of the code base trust another).

Commits
-------

8f157dc Remove redundant references to trusting HttpCache
bug #4240 [Components][EventDispatcher] fix ContainerAwareEventDispatcher definition (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Components][EventDispatcher] fix ContainerAwareEventDispatcher definition

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #4235

Commits
-------

4742859 fix ContainerAwareEventDispatcher definition
minor #4247 [Reference] link translation DIC tags to components section (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Reference] link translation DIC tags to components section

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

The `translation.loader` and `translation.dumper` DIC tags link to the respective sections in the Translation component documentation (in addition to the changes done in #4166).

Commits
-------

9790975 link translation DIC tags to components section
Merge branch '2.3' into 2.4

* 2.3:
  Remove redundant references to trusting HttpCache
  link translation DIC tags to components section
  fix ContainerAwareEventDispatcher definition