Update doc references to ninja to also mention autoninja.

Change-Id: Ib45d3f86a0b68f6d0b10847cf7e3859b640e34a3
Reviewed-on: https://chromium-review.googlesource.com/c/1292403
Commit-Queue: Dirk Pranke <[email protected]>
Reviewed-by: Bruce Dawson <[email protected]>
Cr-Commit-Position: refs/heads/master@{#602453}
10 files changed