Formatting of command-not-found with snap addition could use cleanup

[David Britton]

Example:

--------------------------------

Bionic:

dpb@bierstadt:~[]$ jq
The program 'jq' can be found:
 + snap 'jq'
 * deb 'jq'

Xenial:

dpb@helo:~[]$ jq
The program 'jq' is currently not installed. You can install it by typing:
sudo apt install jq

--------------------------------

Some Observations that could use cleaning up:

1) why '+' for one and '*' for the other?

2) Neither of these things printed were as nice as what show up on xenial, missing what the problem was "program not currently installed", and the what the solution is. Perhaps s/can/cannot/? Still I prefer the previous reading in c-n-f.

3) Users may not be familiar with what 'deb' is, or what 'snap' is for that matter. They are more likely focused on the thing that can help solve their problem (sudo snap install jq, sudo apt install jq).

ii command-not-found 0.3ubuntu18.04.0~pre4 all Suggest installation of packages in interactive bash sessions
ii command-not-found-data 0.3ubuntu18.04.0~pre4 amd64 Set of data files for command-not-found.
ii python3-commandnotfound 0.3ubuntu18.04.0~pre4 all Python 3 bindings for command-not-found.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Zygmunt Krynicki (zyga)]

I'm marking this as confirmed because the formatting is clearly inconsistent.

[Zygmunt Krynicki (zyga)]

In case we get to reword this, my quick proposal:

The program 'jq' is currently not installed. You can install it by typing:
"sudo snap install jq" or "sudo apt install jq". The snap package can be updated
more easily and is generally recommended.