Fix Windows builds from non-ASCII checkout paths (#64947)

## Summary

Closes #64945.

Add UTF-8 header to `rc_content` which is passed to rc.exe as args.

## Testing

Before this change: build failed with `thread 'main' (7344) panicked at
crates\windows_resources\src\windows_resources.rs:122:10:
called `Result::unwrap()` on an `Err` value: Failed("RC.EXE failed to
compile specified resource file")`

Alfter this change: build success.

## Self-review

- [x] I've reviewed my diff for quality, security, reliability, and
performance.
- [x] UI changes follow the
[checklist](https://zed.dev/docs/development/ui-checklist).
- [x] Tests cover the new or changed behavior.

Release Notes:

- N/A

Co-authored-by: Kunall Banerjee <hey@kimchiii.space>

crates/windows_resources/src/windows_resources.rs

@@ -73,8 +73,14 @@ pub fn compile(manifest: bool) -> Result<(), Box<dyn std::error::Error>> {
         version_parts.next().unwrap_or(0),
     );
 
+    // The resource paths can contain non-ASCII characters (e.g. when the
+    // repository lives under a path with such characters). Rust Strings are
+    // encoded using UTF-8, but rc.exe decodes the .rc file using the ANSI code
+    // page by default, which mangles those paths and makes it fail to find the
+    // referenced files, so specify UTF-8 decoding.
     let rc_content = format!(
-        r#"1 ICON "{icon_escaped}"
+        r#"#pragma code_page(65001)
+1 ICON "{icon_escaped}"
 {manifest_line}
 
 1 VERSIONINFO