Simplify and be more direct (#17698)

- Benevity is used by most companies, at least Apple and Google so I'm
  making the instructions for Benevity the default.
- People donating through Benevity might not know that they are using
  Benevity (eg. sometime from Google), so it might not be useful to
  mention the name "Benevity".
- If people search for "Tails" they might end up with hundreds of
  results for animal shelters. Searching for "Riseup Labs" is the way to
  go.
- On Benevity, there is an option called "Tails via Riseup Labs".