fix(wasm): use / paths for workdir

Reimplemented the fix from #2183 to fix building WASM files with Docker
on Windows again. The --workdir argument gives a path inside the Docker
container, so it must use forward slashes regardless of the default path
separator on the host OS.

(cherry picked from commit 755e49e212)

Cargo.toml

@@ -65,6 +65,7 @@ libloading = "0.8.5"
 log = { version = "0.4.22", features = ["std"] }
 memchr = "2.7.4"
 once_cell = "1.19.0"
+path-slash = "0.2.1"
 pretty_assertions = "1.4.1"
 rand = "0.8.5"
 regex = "1.10.6"

cli/loader/Cargo.toml

@@ -26,6 +26,7 @@ fs4.workspace = true
 indoc.workspace = true
 libloading.workspace = true
 once_cell.workspace = true
+path-slash.workspace = true
 regex.workspace = true
 serde.workspace = true
 serde_json.workspace = true

cli/loader/src/lib.rs

@@ -23,6 +23,7 @@ use fs4::FileExt;
 use indoc::indoc;
 use libloading::{Library, Symbol};
 use once_cell::unsync::OnceCell;
+use path_slash::PathBufExt as _;
 use regex::{Regex, RegexBuilder};
 use serde::{Deserialize, Deserializer, Serialize};
 use tree_sitter::Language;
@@ -823,7 +824,7 @@ impl Loader {
                     path.push(src_path.strip_prefix(root_path).unwrap());
                     path
                 };
-                command.args(["--workdir", &workdir.to_string_lossy()]);
+                command.args(["--workdir", &workdir.to_slash_lossy()]);
 
                 // Mount the root directory as a volume, which is the repo root
                 let mut volume_string = OsString::from(&root_path);