Layout example fix (#4463)
Layout example fix (#4463)

* Update forced-layout example

Enforce layout to an explicit block index to allow for other block types

* Update site/examples/forced-layout.tsx

* fix layout example to comply with linting rules

Co-authored-by: Lukas Murdock <dc19de289cc96870613d7d902de6786075f7ec99@gmail.com>
ianstormtaylor/slate,ianstormtaylor/slate