Add IDE support (#8745)

# Description

This adds a set of new flags on the `nu` binary intended for use in
IDEs. Here is the set of supported functionality so far:

* goto-def - go to the definition of a variable or custom command
* type hints - see the inferred type of variables
* check - see the errors in the document (currently only one error is
supported)
* hover - get information about the variable or custom command
* complete - get a completion list at the current position

# User-Facing Changes

No changes to the REPL experience. This only impacts the IDE scenario.

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-utils/standard_library/tests.nu` to run the
tests for the standard library

> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

crates/nu-cli/src/completions/command_completions.rs

@@ -169,7 +169,7 @@ impl Completer for CommandCompletion {
             .take_while(|x| {
                 matches!(
                     x.1,
-                    FlatShape::InternalCall
+                    FlatShape::InternalCall(_)
                         | FlatShape::External
                         | FlatShape::ExternalArg
                         | FlatShape::Literal
@@ -197,7 +197,7 @@ impl Completer for CommandCompletion {
 
         let config = working_set.get_config();
         let commands = if matches!(self.flat_shape, nu_parser::FlatShape::External)
-            || matches!(self.flat_shape, nu_parser::FlatShape::InternalCall)
+            || matches!(self.flat_shape, nu_parser::FlatShape::InternalCall(_))
             || ((span.end - span.start) == 0)
             || is_passthrough_command(working_set.delta.get_file_contents())
         {

crates/nu-cli/src/completions/completer.rs

@@ -490,7 +490,7 @@ fn most_left_variable(
         let result = working_set.get_span_contents(item.0).to_vec();
 
         match item.1 {
-            FlatShape::Variable => {
+            FlatShape::Variable(_) => {
                 variables_found.push(result);
                 found_var = true;
 

crates/nu-cli/src/syntax_highlight.rs

@@ -91,9 +91,10 @@ impl Highlighter for NuHighlighter {
                 FlatShape::Int => add_colored_token(&shape.1, next_token),
                 FlatShape::Float => add_colored_token(&shape.1, next_token),
                 FlatShape::Range => add_colored_token(&shape.1, next_token),
-                FlatShape::InternalCall => add_colored_token(&shape.1, next_token),
+                FlatShape::InternalCall(_) => add_colored_token(&shape.1, next_token),
                 FlatShape::External => add_colored_token(&shape.1, next_token),
                 FlatShape::ExternalArg => add_colored_token(&shape.1, next_token),
+                FlatShape::Keyword => add_colored_token(&shape.1, next_token),
                 FlatShape::Literal => add_colored_token(&shape.1, next_token),
                 FlatShape::Operator => add_colored_token(&shape.1, next_token),
                 FlatShape::Signature => add_colored_token(&shape.1, next_token),
@@ -117,7 +118,9 @@ impl Highlighter for NuHighlighter {
                 FlatShape::Filepath => add_colored_token(&shape.1, next_token),
                 FlatShape::Directory => add_colored_token(&shape.1, next_token),
                 FlatShape::GlobPattern => add_colored_token(&shape.1, next_token),
-                FlatShape::Variable => add_colored_token(&shape.1, next_token),
+                FlatShape::Variable(_) | FlatShape::VarDecl(_) => {
+                    add_colored_token(&shape.1, next_token)
+                }
                 FlatShape::Flag => add_colored_token(&shape.1, next_token),
                 FlatShape::Pipe => add_colored_token(&shape.1, next_token),
                 FlatShape::And => add_colored_token(&shape.1, next_token),