Proposal: don't wrap multiline strings in quotes in pretty-format

[thymikee]

Do you want to request a feature or report a bug?
Breaking change

What is the current behavior?
Multiline strings are wrapped in double quotes (") like this:

Also inner quotes are escaped, which clutters e.g. the snapshot of such string.

What is the proposed behavior?
Since we're inside a template literal, I think it would be nice to treat multiline strings specially and get rid of this clutter:

This would be especially helpful for snapshot helpers like snapshot-diff.

cc @cpojer @aaronabramov @pedrottimark @ferrannp

[cpojer]

Yep.