cmd/go: add missing newlines in printf formats
cmd/go: add missing newlines in printf formats

These are all errors given by module-aware cmd/go, so they must end with
a newline. It looks like they were omitted by mistake.

Fixes #27081.

Change-Id: I19b5803bb48a6d5dd52e857f483278fe20fe246b
Reviewed-on: https://go-review.googlesource.com/129780
Run-TryBot: Daniel Martí <29bf28b42a938ace12a5819da4ed4ba03d82f315@mvdan.cc>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

cloudflare/go,cloudflare/go,josharian/go,CAFxX/go,cloudflare/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,akutz/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go,golang/go,josharian/go,akutz/go,nawawi/go,josharian/go,golang/go,CAFxX/go,golang/go,akutz/go,golang/go,akutz/go,CAFxX/go,golang/go,nawawi/go,akutz/go,CAFxX/go,nawawi/go,josharian/go,josharian/go,golang/go,josharian/go,golang/go,akutz/go,josharian/go,CAFxX/go,nawawi/go,cloudflare/go,akutz/go,josharian/go,nawawi/go,akutz/go,cloudflare/go