diff --git a/library/std/src/alloc.rs b/library/std/src/alloc.rs
index 819d57a934d..8491ff40033 100644
--- a/library/std/src/alloc.rs
+++ b/library/std/src/alloc.rs
@@ -1,4 +1,4 @@
-//! Memory allocation APIs
+//! Memory allocation APIs.
 //!
 //! In a given program, the standard library has one “global” memory allocator
 //! that is used for example by `Box<T>` and `Vec<T>`.