Fix: Content overflowing outside the container in the verse block

[Nikschavan]

Description

This adds overflow: auto CSS property to the verse block so that the content does not overflow the block container.

How Has This Been Tested?

Tested on Chrome (61.0.3163.100) on MacOS High Sierra.

Screenshots (jpeg or gifs if applicable):

Types of changes

• This introduces a CSS change
• Fixes: Content in a verse block isn't constrained by the block container #2821

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows has proper inline documentation.

[youknowriad]

Thanks for fixing this. This looks good to me.
Any design thoughts on this? is this an acceptable tradeoff @jasmussen

[jasmussen]

Scrollbars aren't pretty, but I agree this seems like the most true to the block implementation. The alternative would make it no longer really be a verse block, wouldn't it? So 👍 👍 from me.