Add statement of MSRV to docs
//! [attr-entry]: attr.entry.html
//! [attr-exception]: attr.exception.html
//! [attr-pre_init]: attr.pre_init.html
+//!
+//! # Minimum Supported Rust Version (MSRV)
+//!
+//! The MSRV of this release is Rust 1.32.0.
// # Developer notes
//
