sort: fix grammar in updated Less comment

The rewritten comment didn't sound right to my ears. Tweak it to be
grammatically correct.

Change-Id: Iae7d9f8810fff78cfd964bb3117099bce4479c14
Reviewed-on: https://go-review.googlesource.com/c/go/+/263180
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Robert Griesemer <gri@golang.org>
diff --git a/src/sort/sort.go b/src/sort/sort.go
index 75e0343..cbaa8c3 100644
--- a/src/sort/sort.go
+++ b/src/sort/sort.go
@@ -27,7 +27,7 @@
 	//
 	// Note that floating-point comparison (the < operator on float32 or float64 values)
 	// is not a transitive ordering when not-a-number (NaN) values are involved.
-	// See Float64Slice.Less a correctly implementation for floating-point values.
+	// See Float64Slice.Less for a correct implementation for floating-point values.
 	Less(i, j int) bool
 
 	// Swap swaps the elements with indexes i and j.