Fix spacetime generate running dotnet format in the wrong directory (#3687)

# Description of Changes

`spacetime generate` calls `dotnet format`.. but it did so with
`--folder`, without going to any particular directory. The result would
be that `dotnet format` tries to format _whatever directory it was run
from.

# API and ABI breaking changes

None.

# Expected complexity level and risk

1

# Testing

- [x] `python3 -m smoketests namespaces` no longer hangs on my machine

---------

Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

Author: bfops

crates/cli/src/subcommands/generate.rs

@@ -252,7 +252,7 @@ pub async fn exec_ex(
         }
     }
 
-    if let Err(err) = lang.format_files(paths) {
+    if let Err(err) = lang.format_files(out_dir, paths) {
         // If we couldn't format the files, print a warning but don't fail the entire
         // task as the output should still be usable, just less pretty.
         eprintln!("Could not format generated files: {err}");
@@ -285,10 +285,10 @@ impl clap::ValueEnum for Language {
 }
 
 impl Language {
-    fn format_files(&self, generated_files: BTreeSet<PathBuf>) -> anyhow::Result<()> {
+    fn format_files(&self, project_dir: &PathBuf, generated_files: BTreeSet<PathBuf>) -> anyhow::Result<()> {
         match self {
             Language::Rust => rustfmt(generated_files)?,
-            Language::Csharp => dotnet_format(generated_files)?,
+            Language::Csharp => dotnet_format(project_dir, generated_files)?,
             Language::TypeScript => {
                 // TODO: implement formatting.
             }

crates/cli/src/tasks/csharp.rs

@@ -108,7 +108,7 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
     anyhow::bail!("Built project successfully but couldn't find the output file.");
 }
 
-pub(crate) fn dotnet_format(files: impl IntoIterator<Item = PathBuf>) -> anyhow::Result<()> {
+pub(crate) fn dotnet_format(project_dir: &PathBuf, files: impl IntoIterator<Item = PathBuf>) -> anyhow::Result<()> {
     duct::cmd(
         "dotnet",
         itertools::chain(
@@ -128,6 +128,8 @@ pub(crate) fn dotnet_format(files: impl IntoIterator<Item = PathBuf>) -> anyhow:
             files.into_iter().map_into(),
         ),
     )
+    // This is important because we're running with `--folder`. We want to format the right folder!
+    .dir(project_dir)
     .run()?;
     Ok(())
 }