This commit does two things: 1) it fixes `wasmtime_rust::wasmtime` proc macro by adding the missing import to the `__rt` module, and fixing the scoping inside the macro itself; and 2) it augments the `wasmtime_rust::wasmtime` proc macro with custom error messages in case the implementor forgets the `self` argument in the trait methods.
wasmtime-rust-macro
This is the actual definition of the #[wasmtime] macro, but it's intended that
this crate isn't used directly but rather the wasmtime-rust crate is used
instead.