Is it possible to somehow enable prost-build's cleanup-markdown feature?

[liufuyang]

See what this flag does:

• https://docs.rs/prost-build/0.13.3/prost_build/#feature-flags
• Correct codeblocks to not break cargo test --doc tokio-rs/prost#633

To see the issue, I have this test repo: https://github.com/liufuyang/rust-buf-bigtable-test

buf generate
cargo build
# build works, but when test, the doc-tests will fail with lots of errors
cargo test

...
<ignores a huge error log output here>
...
    src/gen/google.type.rs - google::r#type::PhoneNumber (line 718)
    src/gen/google.type.rs - google::r#type::Quaternion (line 937)
    src/gen/google.type.rs - google::r#type::Quaternion (line 953)

test result: FAILED. 0 passed; 191 failed; 0 ignored; 0 measured; 0 filtered out; finished in 2.13s

error: doctest failed, to rerun pass `--doc`