Link style design guide to mobile design blog post

[1ec5]

Let’s link the “For Style Authors” guide (source) to the “Designing maps for mobile devices” blog post that just went out.

/cc @jmkiley @natslaughter

[natslaughter]

@1ec5 👍

• where exactly would you like this link to be placed in the blog?
• If it requires any additional copy, would you be able to provide copy and amend the blog post?

[1ec5]

Actually, this ticket tracks linking in the other direction, from the guide to the blog post, because the blog post is so thorough. 😄

[jmkiley]

Addressed in #9387