wasmtime: impl ExportLookup for wit_parser::ItemName (#13505)

* wasmtime: impl ExportLookup for wit_parser::ItemName

* upgrade to wasm-tools family 251, wherein wit-parser has ItemName
  and wasm-wave can parse to it
* wasmtime gets a new feature `wit-parser` to take the optional dep on
  wit-parser. (This is already in the transitive dep tree with
  component-model bindgen anyway.) Like with wave, provide a re-export
  of the crate for convenience under wasmtime::component::wit_parser.
* impl ExportLookup for wit_parser::ItemName

* cargo vet: imports for wasm-tools 251 family

* rustfmt

Author: pchickey