Document how to disable automatic sorting in custom completions

[yerlaser]

Resolves: #1670

[ysthakur]

There's also case_sensitive, positional, and completion_algorithm options that would be good to mention. I'm not a fan of the fact that positional exists at all, but if we're documenting the other options, it should probably be documented too. Also not a fan of the fact that it's called completion_algorithm here rather than algorithm, like in $env.config.completions but we can update the docs later if we change that name.

[NotTheDr01ds]

not a fan of the fact that it's called completion_algorithm here rather than algorithm

Lol - I noticed that as well. At first I thought you had added that in your recent PR and was going to suggest changing it before it went public in 0.101, but that's when I realized that it went back way further than your submission :-)

[NotTheDr01ds]

@yerlaser Thanks for taking a first try at this! Unfortunately it's going to need a more systemic change to the chapter. Keep in mind that we start off near the top of the chapter talking about how the completer must return a list. I'll take the blame for that, as I didn't even know about the record return type when I wrote it.

But as @ysthakur mentioned, the differences between the list and record are going to need to be discussed to close #1670, rather than just a section on how to sort alphabetically.

[yerlaser]

Sure, that's fair enough. I'll close this PR then.
Thank you!