tweaks for the web server configuration chapter
Removing extra whitespace
feature #4142 [Cookbook][Configuration] tweaks for the web server configuration chapter (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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[Cookbook][Configuration] tweaks for the web server configuration chapter

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

Tweaks to #3915 as suggested by @weaverryan.

Commits
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93bbd14 tweaks for the web server configuration chapter
Added the schema_filter option to the reference
feature #4150 Added the schema_filter option to the reference (peterrehm)

This PR was submitted for the 2.5 branch but it was merged into the 2.3 branch instead (closes #4150).

Discussion
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Added the schema_filter option to the reference

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

Shall the optional setting be added to XML as well? How?
I am unsure if it is actually to which version this relates to the DoctrineBundle.

Relates to doctrine/migrations#101

Commits
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20cba4e Added the schema_filter option to the reference
Merge branch '2.3' into 2.4

* 2.3:
  Added the schema_filter option to the reference
  Removing extra whitespace
  tweaks for the web server configuration chapter