Image URL tokens are HTML escaped

Problem/Motivation

Using the image style URL token I'm getting values like this:

http://localhost/sites/default/files/styles/small_square/public/some/path/image.jpg?h=209f3b97&itok=p0RR9BOl

Note the "&" in the value that ends in a broken image when the URL is used as img src.

As far I can see, tokens are HTML escaped by core when the callback returns a string value rather than a MarkupInterface impl.

Proposed resolution

Return the image style URL token value enclosed in a Markup object instead as simple string to prevent being escaped and therefore return a malformed URL.

Remaining tasks

• review
• check for other potential similar cases
• test

User interface changes

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

TBD.