Linking to a hidden diff line doesn't expand the diff to show that lin

Summary

During a code review, I was linked to a diff line that was collapsed. I wasn't sure if they linked to a valid line of code.

Steps to reproduce

1. Click the link in this comment: gitlab-org/gitlab-services/design.gitlab.com!2187 (comment 458950091)

2. You're not shown that line in the diff

What is the current bug behavior?

When being linked to a line in a diff that's collapsed, it doesn't show that line because it's collapsed.

What is the expected correct behavior?

I expect the diff to expand to show the line in the link.

Possible fixes

Expand the diff to show the line specified in the link.