Don't display has_many as an attribute.
//!
//! Associations in Diesel are always child-to-parent.
//! You can declare an association between two records with `#[belongs_to]`.
-//! Unlike other ORMs, Diesel has no concept of `#[has_many`]
+//! Unlike other ORMs, Diesel has no concept of `has_many`
//!
//! ```rust
//! # include!("../doctest_setup.rs");
