'snap find <foo>' output is a little agressive when '<foo>' results in no snaps

[Thomi Richards]

Consider the following:

```
  $ snap find inkscape
  error: no snaps found for "inkscape"
```

I think it's a little... rude, to say "error:" It implies that *I've* done something wrong (did I not use the correct command? Was I missing an option flag?), rather than that my search returned no results.

May I suggest instead, that the following would be much nicer:

```
  $ snap find inkscape
  The search "inkscape" returned 0 snaps.

  $ snap find gmail
  Name Version Developer Notes Summary
  gmailfilter 0.0.1a thomi - Programmatically filter gmail messages
  The search "gmail" returned 1 snap.
```

[Mark Shuttleworth (sabdfl)]

Yes, thank you, that's much better language. I would only say that if
there are matches we don't need to provide a count of them, just the
listing is sufficient.

 status: confirmed
 importance: medium

Mark

[Michael Vogt (mvo)]

https://github.com/snapcore/snapd/pull/2377