[Rust] Release 0.56.0

Added

• canonical::RawReason, what stopped a run from modeling a document, and canonical::RawView, carrying it beside the document and a pointer to the subschema the run stopped on.
• ValidationOptions::is_known_format, whether a format of that name is checked under a draft.

Changed

• BREAKING: canonical::CanonicalView::Raw carries a canonical::RawView in place of the document alone.
• Canonicalization of a oneOf whose branches share a region too wide to expand, which spent the document's whole intersection allowance on that choice and kept the document Raw.

Performance

• Preparing or building a schema that names no base URI parses the default one once for the process instead of once per schema.
• Canonicalizing several subschemas of one prepared document compiles each pattern once for the document instead of once per call.
• Canonicalization reads the facets no checker covers once per node instead of once per containment query.