Update book/forms.rst

Fix typo (missing ";") in source code sample for dynamic validation groups
Added final override section
Fixed wrong redirecting
Fixed embedded references
Some minor fixes
Change order of annotations to be the same as the gengerator

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | doctrine
| Fixed tickets |
added docs about child forms customization
CS fixes
Add note about PHP 5.3 behaviour and proxies.
Better wording.
[Doc] add link to Varnish website
fix build errors
remove blank line so that the versionadded directive is rendered properly
fix bash command display in components/console/usage
Merge pull request #2990 from WouterJ/override_validation

Added last missing override section
[#2990] Minor tweaks to new validation overriding instructions
Merge branch '2.2' into 2.3
Merge pull request #3037 from xabbuh/fix-versionadded

remove blank line so that the versionadded directive is render properly
Merge pull request #2993 from WouterJ/issue_2846

Fixed wrong redirection of virtuals -> inherit_data
Merge pull request #3035 from xabbuh/fix-build-errors-2.3

fix build errors