Update configuring_taxation.rst

Hello
Maybe this is as typo at 18th line:
.tax_manager instead of .tax_category?
little service fix
Remove Corebundle price attribute from product_builder.rst
warn about an existing implementation in CoreBundle
fix sylius_settings_get
Fixing installation documentation.
Merge pull request #114 from jjanvier/fix/installation

Fixing installation documentation.
Initial contributing guide, based on Symfony
Fixes, thanks @cordoval
Further fixes
Typos and tweaks
Merge pull request #133 from Sylius/contributing-guide

[WIP] Initial contributing guide, based on Symfony
Final tweaks for now
Update in_services.rst

update service name
Merge pull request #134 from pmartelletti/patch-1

Update in_services.rst
Cookbook how to extend the menus
Update configuration.rst

* Add promotion_subject classes
* Add missing validation groups
Merge pull request #135 from abimus/feature/extending-menu

Cookbook how to extend the menus
Merge pull request #136 from marcaube/patch-1

[PromotionsBundle] Update configuration.rst
Update prototypes.rst

Correct name service 'sylius.builder.prototype'