internal: fix typo
internal: fix typo

Change-Id: I95276a7323b126e132d678978987d89fbe4d851d
GitHub-Last-Rev: f16fe1508e8f73f881fc553add110fab87ba5801
GitHub-Pull-Request: golang/playground#14
Reviewed-on: https://go-review.googlesource.com/c/playground/+/390416
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Trust: Alberto Donizetti <90b16103a35511ced020676f3544f17117fb4c92@gmail.com>
Reviewed-by: Alex Rakoczy <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@golang.org>

golang/playground,golang/playground,golang/playground