go.mod: for consistency with other repos, use 1.22.0 in go.mod

For golang/go#69095

Change-Id: I181e405753866699e70632e5057bb3c7e39e7dfb
Reviewed-on: https://go-review.googlesource.com/c/tools/+/610716
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Robert Findley <rfindley@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

go.mod

@@ -1,6 +1,6 @@
 module golang.org/x/tools
 
-go 1.22.6 // => default GODEBUG has gotypesalias=0
+go 1.22.0 // => default GODEBUG has gotypesalias=0
 
 require (
 	github.com/google/go-cmp v0.6.0