Fix additional missing API doc tags.
Make PHPCS build passing again.
Update code examples to be consistent with other docs.
Remove mention of Role/default as it doesn't exist.

The default role merging was removed in
3abfaeecf30b845ac3a309f011bc460222a923b4 and shouldn't be mentioned in
the docs.

Fixes #3871
Merge commit '5a310847b3058b56323df6c357eece42bb40848a'

Conflicts:
	lib/Cake/Model/Datasource/DboSource.php
Merge commit '03759d2b22ae3ca8fbd644a3b9e749645ddca563'