Rollup merge of rust-lang#80026 - JohnTitor:separator-insensitive, r=Mark-Simulacrum

expand-yaml-anchors: Make the output directory separator-insensitive

Fixes rust-lang#75709

Author: Dylan-DPC

src/tools/expand-yaml-anchors/src/main.rs

@@ -87,7 +87,8 @@ impl App {
         let content = std::fs::read_to_string(source)
             .with_context(|| format!("failed to read {}", self.path(source)))?;
 
-        let mut buf = HEADER_MESSAGE.replace("{source}", &self.path(source).to_string());
+        let mut buf =
+            HEADER_MESSAGE.replace("{source}", &self.path(source).to_string().replace("\\", "/"));
 
         let documents = YamlLoader::load_from_str(&content)
             .with_context(|| format!("failed to parse {}", self.path(source)))?;