Name type of Synonym should be displayed in grey text

When creating or editing a concept, we currently display four name types:

1. Fully Specified
2. Synonym
3. Short
4. Index term

Of these only 1, 3, and 4 have any meaning, so "Synonym" is in fact mapped to a null value. We need to change both the list and the value display so that when the value selected in "Synonym" the "Synonym" text is greyed out to reflect this.