add breaktext doc skeleton

copy paragraph from paint, add empty
example to docs. Fixes bot

TBR=reed@google.com

Docs-Preview: https://skia.org/?cl=173771
Bug: skia:
Change-Id: I4a79f7f8f32f860d0390dbce44669e03bb3a281e
Reviewed-on: https://skia-review.googlesource.com/c/173771
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>
4 files changed