message: Made requirement of setting feature flags to access derive macros more explicit in the documentation.
diff: //! # Derive
  //!
  //! If the `derive` cargo feature is enabled, you can derive `ToSql` and `FromSql` implementations for custom Postgres
  -//! types.
  +//! types. Explicitly, modify your `Cargo.toml` file to include the following:
  +//!
  +//! ```toml
  +//! [dependencies]
  +//! postgres-types = { version = "0.X.X", features = ["derive"] }
  +//! ```
  //!
  //! ## Enums
  //!
  