go.mod: ignore cyclic dependency for tagging

Another followup to CL 439295, sorry. I forgot x/mod is also a problem,
just via a longer path.

For golang/go#48523.

Change-Id: I0e1685bedc0747f8a939cd650d603910450c61d6
Reviewed-on: https://go-review.googlesource.com/c/text/+/442518
Auto-Submit: Heschi Kreinick <heschi@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

go.mod

@@ -3,7 +3,7 @@ module golang.org/x/text
 require golang.org/x/tools v0.1.12 // tagx:ignore
 
 require (
-	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
+	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect tagx:ignore
 	golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect tagx:ignore
 )