message: Reuse "Before hacking on Cargo" to emphasize discussion before hacking
diff: Contributing documentation has moved to the **[Cargo Contributor Guide]**.
  [Cargo Contributor Guide]: https://rust-lang.github.io/cargo/contrib/
  +
  +## Before hacking on Cargo
  +
  +We encourage people to discuss their design before hacking on code. Typically,
  +you [file an issue] or start a thread on the [internals forum] before submitting
  +a pull request. Please read [the process] of how features and bugs are managed
  +in Cargo.
  +
  +[internals forum]: https://internals.rust-lang.org/c/tools-and-infrastructure/cargo
  +[file an issue]: https://github.com/rust-lang/cargo/issues
  +[the process]: https://doc.crates.io/contrib/process/index.html
  