Update table docs.
Update table docs.

The buildRules() method is slightly different than other hooks as
it doesn't use an event on the Table class.

Refs #14250

CakeDC/cakephp,cakephp/cakephp,CakeDC/cakephp,ndm2/cakephp,ADmad/cakephp,ndm2/cakephp,CakeDC/cakephp,ADmad/cakephp,cakephp/cakephp,ADmad/cakephp,CakeDC/cakephp,ADmad/cakephp,cakephp/cakephp,cakephp/cakephp,ndm2/cakephp,ndm2/cakephp