point to where you can contribute

Author: steveklabnik

_posts/2018-09-13-Rust-1.29.md

@@ -93,6 +93,10 @@ The compiler has an API for this, and it only suggests fixing lints that
 we're confident recommend correct code. Over time, as our suggestions
 improve, we'll be expanding this to automatically fix more warnings.
 
+if you find a compiler suggestion and want to help make it fixable, please
+leave a comment on [this
+issue](https://github.com/rust-lang/rust/issues/50723).
+
 ### `cargo clippy`
 
 Speaking of warnings, you can now check out a preview of `cargo clippy` through Rustup.