design: fix typo in code example of 24543

Change-Id: Ia0ebe9b70698898be800632b100d689facd3caf5
GitHub-Last-Rev: 6205e17b95bf3b42bc2504a9c12989f4626d5ea6
GitHub-Pull-Request: golang/proposal#12
Reviewed-on: https://go-review.googlesource.com/103515
Reviewed-by: Austin Clements <austin@google.com>
diff --git a/design/24543-non-cooperative-preemption.md b/design/24543-non-cooperative-preemption.md
index 281b6ae..01f9cda 100644
--- a/design/24543-non-cooperative-preemption.md
+++ b/design/24543-non-cooperative-preemption.md
@@ -265,13 +265,13 @@
 
 ```go
 i, _n, _p := 0, len(s), &s[0]
-if i < _n { goto end } else { goto body }
+if i >= _n { goto end } else { goto body }
 top:
 _p += unsafe.Sizeof(s[0])
 body:
 { b }
 i++
-if i < _n { goto end } else { goto top }
+if i >= _n { goto end } else { goto top }
 end:
 ```