_content/blog/when-generics.md: fix typo in code

Thank you for great article!
 I found a small typo on example code. So, I fixed it!
`cmp` → `less`

Change-Id: I2b595b4be12fe8cf60c69ed66902369378f5ca9c
GitHub-Last-Rev: cc594d707ce1376eaa09d4b0668fea86699c9644
GitHub-Pull-Request: golang/website#171
Reviewed-on: https://go-review.googlesource.com/c/website/+/420734
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
diff --git a/_content/blog/when-generics.md b/_content/blog/when-generics.md
index 47e8acc..92c0dcd 100644
--- a/_content/blog/when-generics.md
+++ b/_content/blog/when-generics.md
@@ -235,7 +235,7 @@
 {{raw `
 	// SortFn sorts s in place using a comparison function.
 	func SortFn[T any](s []T, less func(T, T) bool) {
-		sort.Sort(SliceFn[T]{s, cmp})
+		sort.Sort(SliceFn[T]{s, less})
 	}
 `}}