Fixed typo in SecurityContext PHPDoc

Fixed typo in PHPDoc
Fix missing addExpressionLanguageProvider (used by service container to add expression providers)
fix phpdoc's alignment
bug #12935 [2.6] [Security] Fixed ExpressionVoter - addExpressionLanguageProvider (Luca Genuzio)

This PR was merged into the 2.6 branch.

Discussion
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[2.6] [Security] Fixed ExpressionVoter - addExpressionLanguageProvider

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

Fix missing addExpressionLanguageProvider in [ExpressionVoter](https://github.com/symfony/symfony/blob/2.6/src/Symfony/Component/Security/Core/Authorization/Voter/ExpressionVoter.php), used by [AddExpressionLanguageProvidersPass](https://github.com/symfony/symfony/blob/2.6/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/AddExpressionLanguageProvidersPass.php) to add expression providers.

Commits
-------

6c70bc5 Fix missing addExpressionLanguageProvider (used by service container to add expression providers)
Merge branch '2.5' into 2.6

* 2.5:
  [Form] fixed a maxlength overring on a guessing
  [Debug] Show only unique class candidates
  [SecurityBundle] Firewall providers building - code cleaning
  [Filesystem] symlink use RealPath instead LinkTarget
  [DependencyInjection] Remove duplicate  declaration in PhpDumper
  terminals are not interactive on Travis
  Revert "[DependencyInjection] backport perf optim"
  [WebProfilerBundle] replaced pattern to path attribute in routes definitions.
  fix phpdoc's alignment
  Fixed the AuthenticationProviderInterface alignment
  Fixed the proxy-manager version constraint
  [FrameworkBundle][Template name] avoid  error message for the shortcut notation.
  [DependencyInjection] perf optim: call dirname() at most 5x
  [DependencyInjection] backport perf optim
  Fixed #12845 adding a listener to an event that is currently being dispatched will not result into a fatal error in TraceableEventDispatcher [EventDispatcher]
  [2.5] Remove possible call_user_func()
  [2.3] Remove possible call_user_func()

Conflicts:
	src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services1-1.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services1.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services11.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services12.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services8.php
	src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9.php
Merge branch '2.6' into 2.7

* 2.6: (24 commits)
  [Form] fixed a maxlength overring on a guessing
  [Debug] Show only unique class candidates
  [SecurityBundle] Firewall providers building - code cleaning
  [Filesystem] symlink use RealPath instead LinkTarget
  [DependencyInjection] Remove duplicate  declaration in PhpDumper
  terminals are not interactive on Travis
  Revert "[DependencyInjection] backport perf optim"
  [WebProfiler] Tweaked ajax requests toolbar css reset
  [WebProfilerBundle] replaced pattern to path attribute in routes definitions.
  fix phpdoc's alignment
  Fix missing addExpressionLanguageProvider (used by service container to add expression providers)
  Fixed the AuthenticationProviderInterface alignment
  Fixed the proxy-manager version constraint
  Fix missing space in label_attr
  fix DumpDataCollectorTest after CS changes
  avoid risky tests
  Fixed typo in SecurityContext PHPDoc
  [FrameworkBundle][Template name] avoid  error message for the shortcut notation.
  [DependencyInjection] perf optim: call dirname() at most 5x
  [DependencyInjection] backport perf optim
  ...
Merge branch '2.7'

* 2.7: (26 commits)
  [Form] fixed a maxlength overring on a guessing
  [Debug] Show only unique class candidates
  [FrameworkBundle] make GetSetMethodNormalizer available by default
  [SecurityBundle] Firewall providers building - code cleaning
  [Filesystem] symlink use RealPath instead LinkTarget
  [DependencyInjection] Remove duplicate  declaration in PhpDumper
  terminals are not interactive on Travis
  Revert "[DependencyInjection] backport perf optim"
  [WebProfiler] Tweaked ajax requests toolbar css reset
  [WebProfilerBundle] replaced pattern to path attribute in routes definitions.
  fix phpdoc's alignment
  Fixed deprecation version
  Fix missing addExpressionLanguageProvider (used by service container to add expression providers)
  Fixed the AuthenticationProviderInterface alignment
  Fixed the proxy-manager version constraint
  Fix missing space in label_attr
  fix DumpDataCollectorTest after CS changes
  avoid risky tests
  Fixed typo in SecurityContext PHPDoc
  [FrameworkBundle][Template name] avoid  error message for the shortcut notation.
  ...