Escape SSI virtual in generated response
Fix CS
minor #11851 [HttpKernel] Escape SSI virtual in generated response (Jérémy Derussé)

This PR was merged into the 2.6-dev branch.

Discussion
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[HttpKernel] Escape SSI virtual in generated response

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

If a template with an `<!--#inlude -->` tag  is configured with an "virtual" containing a `'` ; the HttpCache will generate invalide php code.

See #11845 for the same issue on `<esi>` tags

Commits
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b50a434 Fix CS
1862427 Escape SSI virtual in generated response