Imprecision in `multipass help find` message

```
$ multipass help find
Usage: multipass find [options] [][]
Lists available images matching for creating instances from.
With no search string, lists all aliases for supported Ubuntu releases.

Options:
-h, --help Display this help
-v, --verbose Increase logging verbosity, repeat up to three times for more
detail

Arguments:
string An optional value to search for in [] format,
where can be either ‘release’ or ‘daily’. If
is omitted, it will search ‘release‘ first, and if no matches
are found, it will then search ‘daily‘. can be a
partial image hash or an Ubuntu release version, codename or
alias.
```

`multipass find snapcraft:` is a valid command, so the help message for the argument should not limit remotes to `release` and `daily`. Perhaps adding `snapcraft` to the message is enough for now.

Additionally, there should be brackets around `` in `[]` (as is already the case in the "usage" message.

Locate the help text produced by `multipass help find` and compare it with the issue's captured output. Update the remote description to include `snapcraft` and show brackets around ``; verify the corrected wording by running `multipass help find`.

Written by the indexing model from the issue text.