Move post-edit font-family rule to Vector-specific selector

The post-edit confirmation message is rendered in the same font-family
across skins due to the font-family rule not being scoped to Vector. This
change moves the font-family rule to a Vector-specific selector, making
the font-family in other skins the inherited one.

Change-Id: I6dd0d0aa5fc6f4773529bec416a7ab35606a1bbc
Merge "Move post-edit font-family rule to Vector-specific selector"