Update skia docs to stop referring to NeedsManualRebaseline

No-Try: true
Docs-Preview: https://skia.org/?cl=179782
Bug: chromium:621126
Change-Id: Iee8d6d86a5cda31d84d4ebe708c7f6fd9f80f78b
Reviewed-on: https://skia-review.googlesource.com/c/179782
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2 files changed