backport #12489
Rename Symfony2 to Symfony
minor #12565 Rename Symfony2 to Symfony (romainneutron)

This PR was merged into the 2.3 branch.

Discussion
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Rename Symfony2 to Symfony

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

Replaces #12563

Commits
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0a76b7e Rename Symfony2 to Symfony
bug #12550 [FrameworkBundle] backport #12489 (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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[FrameworkBundle] backport #12489

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

Commits
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556eff1 backport #12489
[Debug] fix error message on double exception
bug #12553 [Debug] fix error message on double exception (nicolas-grekas)

This PR was submitted for the 2.6 branch but it was merged into the 2.3 branch instead (closes #12553).

Discussion
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[Debug] fix error message on double exception

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

Commits
-------

1ed7606 [Debug] fix error message on double exception