test(lexer): Ensure frontmatter w/ crlf works

tests/ui/.gitattributes

@@ -3,4 +3,5 @@ json-bom-plus-crlf.rs -text
 json-bom-plus-crlf-multifile.rs -text
 json-bom-plus-crlf-multifile-aux.rs -text
 trailing-carriage-return-in-string.rs -text
+frontmatter-crlf.rs -text
 *.bin -text

tests/ui/frontmatter/frontmatter-crlf.rs

@@ -0,0 +1,14 @@
+#!/usr/bin/env -S cargo -Zscript
+---
+[dependencies]
+clap = "4"
+---
+
+//@ check-pass
+// ignore-tidy-cr
+
+// crlf line endings should be accepted
+
+#![feature(frontmatter)]
+
+fn main() {}