This PR was merged into the master branch.

Discussion
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Updates to DI config for 3.3

Hi guys!

WIP changes the new DI changes in 3.3! Woohoo! Some notes for myself:

This relates to, oh, just these 10+ issues :). Assume they will all be closed by this one PR - before merge, if any of them aren't covered, I'll remove them.

TODOS later (some might already be done)
- update to use `debug:container --types` (symfony/symfony#22624)
- update all other documents for possible changes for autowiring and autoconfigure
- new page for existing Symfony users to explain the changes
- update autowire section to talk about using aliases
- document instanceof and also the ability to add configuration to the PSR4 loader
- some links in the controller go to the API docs of `Controller`. But this is wrong, the methods
now live in `ControllerTrait`... but the API docs for traits is basically broken: http://api.symfony.com/master/Symfony/Bundle/FrameworkBundle/Controller/ControllerTrait.html
- how should we pass a parameter to a controller?
- do Twig extensions still need to be public? If so, the example in `service_container` about autoconfigure is still not quite right

Definitely included in this PR
* #7544
* #7482
* #7339
* #7672

Not included in this PR (but related to DI changes)
* #7329
* #7782
* #7777
* #7706
* #7608
* #7538
* #7441
* #7255
* ~~#7041~~
* ~~#7445~~
* ~~#7444~~
* ~~#7436~~

Commits
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22adfbd removing duplicate target
12c4944 Tweaks after amazing review from @GuilhemN and @xabbuh
cac3c6c Merge remote-tracking branch 'origin/master' into di-3.3-changes
2229fd3 Merge remote-tracking branch 'origin/master' into di-3.3-changes
5452c61 Adding section about public: false
ee27765 Adding versionadded
bc7088d Merge remote-tracking branch 'origin/di-3.3-changes' into di-3.3-changes
443aec2 Merge pull request #7857 from GuilhemN/patch-1
89e12de bad link
6de83e2 fixing build problem
759e9b2 last tweaks from feedback
45500b3 Adding details and usages of fetching the service as a controller arg
70178d1 adding note about autoconfigure
6e6ed94 more tweaks
0e48bd8 [WIP] Updates to DI config for 3.3
9ab27f0 Add xml files
2636bea bad link
c45daf4 fixing build problem
9e84572 last tweaks from feedback
049df7d Adding details and usages of fetching the service as a controller arg
105801c adding note about autoconfigure
2d11347 more tweaks
8433fc1 [WIP] Updates to DI config for 3.3