Typo fix: "the a" -> "the"
//! release of Rust. They are toml files, typically downloaded from
//! e.g. static.rust-lang.org/dist/channel-rust-nightly.toml. They
//! describe where to download, for all platforms, each component of
-//! the a release, and their relationships to each other.
+//! the release, and their relationships to each other.
//!
//! Installers use this info to customize Rust installations.
//!
