Change "attributes" to "attribute" in `Alloc`'s docs

diff --git a/src/libcore/alloc.rs b/src/libcore/alloc.rs
index c8a3a2d9fe5a18205dfdd2278c1bbfa9142d26c0..a6dc19220c95039ed589fcdf9a28f7293f08ef0e 100644 (file)
--- a/src/libcore/alloc.rs
+++ b/src/libcore/alloc.rs
@@ -388,7 +388,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 }
 
 /// A memory allocator that can be registered as the standard library’s default
-/// through the `#[global_allocator]` attributes.
+/// through the `#[global_allocator]` attribute.
 ///
 /// Some of the methods require that a memory block be *currently
 /// allocated* via an allocator. This means that: