internal/runtime/exithook: fix a typo

That is the say -> That is to say

Change-Id: I4a19d4c500103e16e6ae55f41a9fbdddd4bb84a8
GitHub-Last-Rev: 571d49a
GitHub-Pull-Request: #74741
Reviewed-on: https://go-review.googlesource.com/c/go/+/690195
Reviewed-by: Michael Knyszek <[email protected]>
Reviewed-by: Michael Pratt <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Michael Pratt <[email protected]>
Auto-Submit: Michael Knyszek <[email protected]>

Author: callthingsoff

src/internal/runtime/exithook/hooks.go

@@ -8,7 +8,7 @@
 // from a safe context (e.g. not an error/panic path or signal
 // handler, preemption enabled, allocation allowed, write barriers
 // allowed, etc), and that the exit function F will be invoked under
-// similar circumstances. That is the say, we are expecting that F
+// similar circumstances. That is to say, we are expecting that F
 // uses normal / high-level Go code as opposed to one of the more
 // restricted dialects used for the trickier parts of the runtime.
 package exithook