GN: Fix some typos in the documentation.

BUG=

Review-Url: https://codereview.chromium.org/2616523002
Cr-Original-Commit-Position: refs/heads/master@{#441257}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 0c1dd9de8c008dd49dfbc9c646cd87027db3d577
2 files changed
tree: 8e1d36e7da08a53506c6a4d61297271019589e1f
  1. tools/