Done with:

go get [email protected]
go mod tidy
go fix ./...

Using go1.21.3.

Also update code generators to use only the new go:build lines,
not the old +build ones.

For golang/go#60268.

Change-Id: I832981d939ab0aad5c941555a6a4cd005958a189
Reviewed-on: https://go-review.googlesource.com/c/text/+/534242
Reviewed-by: Damien Neil <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>