Syntax for Conditional on Taxonomy Term not documented

[ssyberg]

Full discussion here: statamic/cms#6488

Most relevant excerpt:
I think this is the answer, though I'm not totally sure if these are the right identifiers. The secret sauce here missing from the docs is the <some sort of handle>::

if:
  <taxonomny_terms_field_handle>: 'contains <taxonomy_handle???>::<taxonmy_term_slug>'

So in my current example it looks like this:

unless:
  news_types: 'contains news_types::media-mentions'