Docs: rename examples files to match names

Change-Id: I9a6b2780cfdd91cdd16d5a08eb9ba1214492cb7e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201982
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
1078 files changed