Fix text for CDAs serving in more than one country

From @awmarrs:

> When a charge d’affaires ad interim serves in more than one country, the auto-generated text should not say “accredited,” since they don’t present credentials, e.g., https://history.state.gov/departmenthistory/people/schwartz-stephen-michael.
> 
> Can we change this to something like “Also served at …” instead?