prepare for capnpc-v0.23.2 release

prepare for capnpc-v0.23.1 release

restore previous evalaute_impl in calculator example

Naively using async/await open the possibility of double borrows,
as pointed out by clippy.

restore previous evalaute_impl in calculator example

Naively using async/await open the possibility of double borrows,
as pointed out by clippy.

restore previous evalaute_impl in calculator example

Naively using async/await open the possibility of double borrows,
as pointed out by clippy.

restore previous evalaute_impl in calculator example

Naively using async/await open the possibility of double borrows,
as pointed out by clippy.

std::future -> core::future in generated code

std::future -> core::future in generated code

std::future -> core::future in generated code

std::future -> core::future in generated code