Cannot add text after creating an image in official Slate image example

[Silas Rhyneer]

Description
When you insert an image in the official image example, you cannot insert text after that image

Steps
To reproduce the behavior:

1. Go to the official slate image example sandbox: https://www.slatejs.org/examples/images
2. Try to type any text after the picture of the sheep

You can also replicate this bug by deleting all the text and inserting an image, and then trying to add text after that image.

Expectation
Upon inserting an image, you should be able to click on the image, press "enter" and have a new line appear after the image.

Environment

• Slate Version: Unsure—whichever is officially hosted on slate docs
• Operating System: MacOS
• Browser: Safari