Update docs for query builder

[MasterOdin]

The docs for the query builder:

https://github.com/cakephp/phinx/blob/615485032e67d9500cbfa2e53acdb0449e26f191/docs/en/migrations.rst?plain=1#L1646-L1676

These are out of date and need to be updated to make reference to the specific builder methods (e.g. getSelectBuilder) that people are supposed to use now.