gn docs: Add a missing closing paren.

BUG=none

Review-Url: https://codereview.chromium.org/2852443002
Cr-Original-Commit-Position: refs/heads/master@{#467724}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: dd1ae15f741af316df1aefc7df74aa4427839250
2 files changed
tree: c9ac0dd18d3c9910dba64d21fe3900591ba2475c
  1. tools/