slots shouldn't have `structured_pattern`s and asserted `pattern`s

[turbomam]

nor should that happen via slot_usage

the solution is to remove asserted patterns from some "source" schema file when there is a structured_patten but to include a --materialized-patterns generated file in each build or release

[turbomam]

we should make sure that the patterns, after being removed, can be recreated verbait form the structured_patterns

watch out for line wraps!

[lschriml]

Please add an example.