feat: LSP path completion (#5712)

# Description

## Problem

Part of #1577

## Summary

LSP will now suggest completions anywhere there's a Path. Here are some
scenarios:

### Autocomplete functions in full paths, with parameters


![lsp-complete-function](https://github.com/user-attachments/assets/48f1bc08-50e6-4c10-b22a-8c99dd67736d)

### Autocomplete functions when they exist in a use statement


![lsp-complete-function-after-use](https://github.com/user-attachments/assets/74f27049-ec4d-4722-972b-586e1f834969)

### Built-in functions are also suggested


![lsp-builtin-functions](https://github.com/user-attachments/assets/17ecd98b-7001-4981-a1ba-f54ec4aa8ca3)

### Autocomplete local variables


![lsp-local-var](https://github.com/user-attachments/assets/671efe94-4a4d-4cd8-a66b-982d67276383)

### Autocomplete types in several type positions


![lsp-suggest-type](https://github.com/user-attachments/assets/e52a965a-59b1-47a9-aff2-c5c7cbce8e37)

### Built-in types are also suggested


![lsp-builtin-type](https://github.com/user-attachments/assets/9b3c0bb6-b429-447a-9b13-7d1d939127dc)

### Autocomplete type parameters


![lsp-type-parameter](https://github.com/user-attachments/assets/e8bd3e8d-ac20-48f9-b416-426d9ddfcd4e)

## Additional Context

Sorry for the large diff, the bulk of it is traversing the AST. I
thought about using something like the Visitor pattern, but I'm not
exactly sure how it would look in Rust and whether it would greatly
reduce the amount of code. It could be a separate refactor, though! (and
we have tons of tests now, so it should be safe to do too).

Another big chunk of code is tests... So the actual logic isn't that
large.

Some more things could be done on top of this, like suggesting `Self` if
it's available, but I wanted to stop making this PR bigger 😊

## Documentation

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

compiler/noirc_frontend/Cargo.toml

@@ -32,12 +32,12 @@ tracing.workspace = true
 petgraph = "0.6"
 rangemap = "1.4.0"
 lalrpop-util = { version = "0.20.2", features = ["lexer"] }
+strum = "0.24"
+strum_macros = "0.24"
 
 
 [dev-dependencies]
 base64.workspace = true
-strum = "0.24"
-strum_macros = "0.24"
 
 [build-dependencies]
 lalrpop = "0.20.2"

compiler/noirc_frontend/src/hir/def_map/module_data.rs

@@ -38,7 +38,7 @@ impl ModuleData {
         }
     }
 
-    pub(crate) fn scope(&self) -> &ItemScope {
+    pub fn scope(&self) -> &ItemScope {
         &self.scope
     }
 

compiler/noirc_frontend/src/lexer/token.rs

@@ -883,8 +883,7 @@ impl AsRef<str> for SecondaryAttribute {
 
 /// Note that `self` is not present - it is a contextual keyword rather than a true one as it is
 /// only special within `impl`s. Otherwise `self` functions as a normal identifier.
-#[derive(PartialEq, Eq, Hash, Debug, Copy, Clone, PartialOrd, Ord)]
-#[cfg_attr(test, derive(strum_macros::EnumIter))]
+#[derive(PartialEq, Eq, Hash, Debug, Copy, Clone, PartialOrd, Ord, strum_macros::EnumIter)]
 pub enum Keyword {
     As,
     Assert,

tooling/lsp/Cargo.toml

@@ -22,6 +22,7 @@ noirc_frontend.workspace = true
 noirc_artifacts.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+strum = "0.24"
 tower.workspace = true
 async-lsp = { workspace = true, features = ["omni-trait"] }
 serde_with = "3.2.0"