Adjust documentation in HAIR.

Author: Centril

src/librustc_mir/hair/pattern/mod.rs

@@ -162,7 +162,7 @@ pub enum PatternKind<'tcx> {
 
     /// Matches against a slice, checking the length and extracting elements.
     /// irrefutable when there is a slice pattern and both `prefix` and `suffix` are empty.
-    /// e.g., `&[ref xs..]`.
+    /// e.g., `&[ref xs @ ..]`.
     Slice {
         prefix: Vec<Pattern<'tcx>>,
         slice: Option<Pattern<'tcx>>,