fix: dev: Removed `VowsAssertionError` and `_AssertionNotFoundError`

Should not have been here after merging the changes from refactoring for preggy.  Well, they’re gone _now_...
dev: chg: @refactor @minor Removed async aliases in Vows class

These classes are never accessed through the Vows class…and they’re not intended for client code use.
chg: dev: @minor Added comment “dividers”
chg: dev: @minor Put reporting-related vows into `tests/reporting/`