fmt: fix incorrect doc comment
I noticed that the comment incorrectly stated 'WriteString implemented WriteString', it should be 'implemented io.StringWriter' instead.
Change-Id: I844a8c805e5f0c32b5aea68c4bba6982f6fcc8a7
GitHub-Last-Rev:
a0d93b6e9d3c2a508d1f3c0ce23e98274ec421fb
GitHub-Pull-Request: golang/go#69546
Reviewed-on: https://go-review.googlesource.com/c/go/+/614575
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Rob Pike <r@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>