Fix a typo in the gn gen help for QtCreator generator (introduced in https://codereview.chromium.org/1883093002/)

BUG=

Review-Url: https://codereview.chromium.org/1979813002
Cr-Original-Commit-Position: refs/heads/master@{#393795}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 457e2cd70b7aeab763f7ee35bc60c62d36121c26
1 file changed
tree: c414f2a22206b801841d79e6555ca3045284d1dd
  1. tools/