message: doc(changelog) Add and
diff: ## **[Unreleased]**
  +- [#925](https://github.com/wasmerio/wasmer/pull/925) Host functions can be closures with a captured environment.
  +- [#917](https://github.com/wasmerio/wasmer/pull/917) Host functions (aka imported functions) may not have `&mut vm::Ctx` as first argument, i.e. the presence of the `&mut vm::Ctx` argument is optional.
  +- [#915](https://github.com/wasmerio/wasmer/pull/915) All backends share the same definition of `Trampoline` (defined in `wasmer-runtime-core`).
  - [#921](https://github.com/wasmerio/wasmer/pull/921) In LLVM backend, annotate all memory accesses with TBAA metadata.
  - [#883](https://github.com/wasmerio/wasmer/pull/883) Allow floating point operations to have arbitrary inputs, even including SNaNs.
  - [#856](https://github.com/wasmerio/wasmer/pull/856) Expose methods in the runtime C API to get a WASI import object
  