fileUriToRelativeImportPath function
Converts a file: URI from analyzer element metadata into a relative
import path safe to embed in generated Dart source on all platforms.
Windows file paths use backslashes; when written into Dart string literals,
sequences like \r in \routes become carriage returns and break compilation.
Implementation
String fileUriToRelativeImportPath(String uri) {
final filePath = Uri.parse(uri).toFilePath();
return p.relative(filePath).replaceAll(r'\', '/');
}