dice: clean up the dice "choose" command output (fix #1420)

[Exirel]

See issue #1420 and PR #1421 that I used as my starting point.

Following my comment on #1420 I decided to go with a PR that:

• strip the space from the input,
• properly format delimiter in the ouput,
• add some test example while I was at it,
• and use the space \s as a last-resort delimiter, because why not,

which improve coverage and make for a better output.

EDIT: we discussed another option, which I implemented afterward, to use comma as an output delimiter in all cases and to add quotation marks when needed.

Example with comma ,:

[nick] .choose a, b, c
[Sopel] Your options: a, b, c. My choice: b

Example with comma , (without spaces):

[nick] .choose a,b,c
[Sopel] Your options: a, b, c. My choice: b

Example with pipe |:

[nick] .choose a | b | c
[Sopel] Your options: a, b, c. My choice: b

Example with pipe | (without spaces):

[nick] .choose a|b|c
[Sopel] Your options: a, b, c. My choice: b

Example with space \s:

[nick] .choose a b c
[Sopel] Your options: a, b, c. My choice: b

Example with pipe | but there are comma in some options:

[nick] .choose a, b and c | a, b | just a
[Sopel] Your options: "a, b and c", "a, b", just a. My choice: a, b

[dgw]

This looks good so far! I'm just going to leave a note, for now, but it doesn't need to be addressed immediately. It can wait until after Sopel 6.6.0 is (finally) released.

Commit fb4eb44 duplicates what #1421 does, just in a slightly different way. This PR should be amended (eventually) to make sure only one strip() operation survives into Sopel 7.

[Exirel]

Yes indeed! It'll be done.

[Exirel]

First rebase, just to clean up the split thing. The second one will change the output delimiter to a comma, with option quoted when needed.

[Exirel]

Second rebase, to change the output delimiter to the discussed one (only comma, quote when needed).

@dgw it should be good now!

[dgw]

So, I did manage to trip this up with quoted input:

<dgw>   .ch "foo, bar", spam, "egg, bacon"
<Sopel> dgw: Your options: "foo, bar", spam, "egg, bacon". My choice: "egg

But… I don't think handling that kind of case is worth it. This is actually exactly why the module supports so many delimiters. Using something other than , between items works just fine:

<dgw>   .ch "foo, bar"|spam|"egg, bacon"
<Sopel> dgw: Your options: ""foo, bar"", spam, ""egg, bacon"". My choice: "foo, bar"

The nested quotes look a little weird, admittedly, but this is going to be an exceedingly rare case. So I'm not going to mind it. We can always come back to this function post-7.0.0 if it turns out to be an issue.