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>

src/command.rs

@@ -36,7 +36,8 @@ pub(crate) fn gather_commandline_args() -> (Vec<String>, String, Vec<String>) {
             | "--env-config" => args.next().map(|a| escape_quote_string(&a)),
             #[cfg(feature = "plugin")]
             "--plugin-config" => args.next().map(|a| escape_quote_string(&a)),
-            "--log-level" | "--log-target" | "--testbin" | "--threads" | "-t" => args.next(),
+            "--log-level" | "--log-target" | "--testbin" | "--threads" | "-t"
+            | "--ide-goto-def" | "--ide-hover" | "--ide-complete" => args.next(),
             _ => None,
         };
 
@@ -95,6 +96,12 @@ pub(crate) fn parse_commandline_args(
         )) = pipeline.elements.get(0)
         {
             let redirect_stdin = call.get_named_arg("stdin");
+            let ide_goto_def: Option<Value> =
+                call.get_flag(engine_state, &mut stack, "ide-goto-def")?;
+            let ide_hover: Option<Value> = call.get_flag(engine_state, &mut stack, "ide-hover")?;
+            let ide_complete: Option<Value> =
+                call.get_flag(engine_state, &mut stack, "ide-complete")?;
+            let ide_check = call.get_named_arg("ide-check");
             let login_shell = call.get_named_arg("login");
             let interactive_shell = call.get_named_arg("interactive");
             let commands: Option<Expression> = call.get_flag_expr("commands");
@@ -180,6 +187,10 @@ pub(crate) fn parse_commandline_args(
                 log_level,
                 log_target,
                 execute,
+                ide_goto_def,
+                ide_hover,
+                ide_complete,
+                ide_check,
                 table_mode,
             });
         }
@@ -212,6 +223,10 @@ pub(crate) struct NushellCliArgs {
     pub(crate) log_target: Option<Spanned<String>>,
     pub(crate) execute: Option<Spanned<String>>,
     pub(crate) table_mode: Option<Value>,
+    pub(crate) ide_goto_def: Option<Value>,
+    pub(crate) ide_hover: Option<Value>,
+    pub(crate) ide_complete: Option<Value>,
+    pub(crate) ide_check: Option<Spanned<String>>,
 }
 
 #[derive(Clone)]
@@ -268,6 +283,29 @@ impl Command for Nu {
                 SyntaxShape::String,
                 "start with an alternate environment config file",
                 None,
+            )
+            .named(
+                "ide-goto-def",
+                SyntaxShape::Int,
+                "go to the definition of the item at the given position",
+                None,
+            )
+            .named(
+                "ide-hover",
+                SyntaxShape::Int,
+                "give information about the item at the given position",
+                None,
+            )
+            .named(
+                "ide-complete",
+                SyntaxShape::Int,
+                "list completions for the item at the given position",
+                None,
+            )
+            .switch(
+                "ide-check",
+                "run a diagnostic check on the given source",
+                None,
             );
 
         #[cfg(feature = "plugin")]