The comment dialog was looking pretty old, with its black borders and
square corners. It was also a bit annoying that the text field would
shrink when showing the dirty state message.

This tweaks the style a bit, making the dialog a bit softer, with
rounded corners and lighter borders. It's also a bit larger, giving more
room for comment entry.

The status message is gone, preventing that jump. Instead, an
"(unsaved)" label appears on the dialog header.

The "Other reviews" hasn't really been changed any. It's still the same
sorta ugly box it was before, with the exception being that the View and
Reply actions are no longer ugly black-outlined boxes. They're now
simple links. This box will need its own restyle/redesign at some point.

Played with the dialog, resized it, entered text, viewed comments.

Everything looked and acted as expected.
Unit tests pass.