* prover.cpp: loop merge conflict error now points to loop header as source. Previously the error message was anchored to the return type that precedes the conflicting one. This makes sense for functions where the return type is inferred by the return points, but not for loops where we always know the type (from the header).
* renamed `sc_prompt_*` API functions * removed `sc_set_autocomplete_scope` * prefixed all prompt relevant API functions with `sc_prompt_*` * added support for prompt autocompletion callback * console: use autocompletion callback to implement scope completion
* type reprs now largely reflect valid constructor calls so users know how to construct the type * `signed integer <width>` or `signed <integer-type>` can be used to construct / convert integer types * `_:` is a valid alias for `Arguments` * `raises` can be used as an infix operator