Clarify the scope-related explanation

Based on the review made by dtolnay.

diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
index 6625d4659dcac95dff8da90baefa8d2aee32c022..37c8125b0984acaa364159019d0004abae6c6784 100644 (file)
--- a/src/libstd/sync/mutex.rs
+++ b/src/libstd/sync/mutex.rs
@@ -108,9 +108,8 @@
 /// *guard += 1;
 /// ```
 ///
-/// It is sometimes necessary to manually drop the mutex
-/// guard to unlock it as soon as possible. If you need the resource until the end of
-/// the scope, this is not needed.
+/// It is sometimes necessary to manually drop the mutex guard
+/// to unlock it sooner than the end of the enclosing scope.
 ///
 /// ```
 /// use std::sync::{Arc, Mutex};