Consider appending "(optional)" note (or similar) to non-required field labels

[cjg89]

Since we hide required field asterisks with CSS, it would be helpful to users to have an alternate means of distinguishing between required and optional fields. We could potentially use a filter of some sort on individual field labels and append a "optional" phrase at the end if the field is not required and doesn't already have a string like "optional" in the label text value.