[SizzleUnrlsd]

Summary

Syntax item of #71 found by the broadened corpus: class keyword arguments and general with targets.

• Acceptance tests first (test: define class keyword arguments and general with targets), implementation follows.
• class Task(Base, metaclass=Register): the HIR Class keeps its keywords; the scope analysis and the lowering of a local class evaluate them where the class is defined. Methods of such classes are analysed like any other.
• with ctx() as self.conn, as d["k"], as (a, b): a WithItem target is any assignable target, bound through the scope analysis and stored through the lowering like an assignment, so it receives what the context manager enters.
• Snapshots: luigi goes from 245 to 259 files analysed (4 462 to 5 169 functions), httpie to 132/132, the FastAPI template to 42/43; the 18 syntax-error notes disappear and two findings appear in the newly analysed files, a subprocess call in httpie's upload tests and a credential-named field default in the template's models.
• The usage guide lists the two forms.

Part of #71.