LSP: Show fn/value signature instead of a module name

[Zhomart]

RFC: What do you think about this proposal?

Motivation: I want to see the function or value signatures when autocompleting, it allows quickly understand what function does and what does it return. The module name can be deduced by the prefix before ".".

Before	After

Before	After

Before	After

[lpil]

How does the programmer know which module each item comes from after this case? The type information was also already included in the completion information, typically shown for the selected option.

The Rust example you've shown in the issue priorities the module also, and modules are less important in Rust than Gleam, so we have more need to show them.