Return LSP 3.17 labelDetails on completion items

[lukaszsamson]

annotate completions that require alias insertions deprioretize alias insertion
fix crash when completing one line source file

Examples from vscode

Addresses #774

[scohen]

I like the alias XXX annotation, that fixes the earlier problems.

Slight nitpick though: It's puzzling to me why typing Enum. would have EmptyError and OutOfBoundsException show up before Enum.all. Exceptions should be sorted pretty far down in the list of possible completions, but this does bring up structs, which are probably as important as functions, but shouldn't be super high on the list for this specific completion.

[lukaszsamson]

Slight nitpick though: It's puzzling to me why typing Enum. would have EmptyError and OutOfBoundsException show up before Enum.all. Exceptions should be sorted pretty far down in the list of possible completions, but this does bring up structs, which are probably as important as functions, but shouldn't be super high on the list for this specific completion.

Nice idea. It was easy to deprioretize exceptions.