fmt: add example for Fprintln
fmt: add example for Fprintln

Change-Id: Idc4aa53e443b89eeba496d00f6b409268e29ec21
Reviewed-on: https://go-review.googlesource.com/132241
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

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