cmd/go: update comment to not say GO386 does not exist

GO386 was removed by CL 258957, but it was restored by CL 260017.

Change-Id: Iced49ca61512a0f2ef513acbf9700a87ac964c68
Reviewed-on: https://go-review.googlesource.com/c/go/+/580675
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/cmd/go/internal/envcmd/env.go b/src/cmd/go/internal/envcmd/env.go
index 1680753..bff3fe5 100644
--- a/src/cmd/go/internal/envcmd/env.go
+++ b/src/cmd/go/internal/envcmd/env.go
@@ -681,10 +681,7 @@
 }
 
 // sortKeyValues sorts a sequence of lines by key.
-// It differs from sort.Strings in that keys which are GOx where x is an ASCII
-// character smaller than = sort after GO=.
-// (There are no such keys currently. It used to matter for GO386 which was
-// removed in Go 1.16.)
+// It differs from sort.Strings in that GO386= sorts after GO=.
 func sortKeyValues(lines []string) {
 	sort.Slice(lines, func(i, j int) bool {
 		return lineToKey(lines[i]) < lineToKey(lines[j])