Escape windows path backslashes in JSON output

src/aion/Tracer.output.cc

@@ -155,7 +155,9 @@ void write_speedscope_json(std::string const &filename)
             out << ",";
         out << "{";
         out << "\"name\":\"" << (std::string(loc->name).empty() ? beautify_function_name(loc->function) : loc->name) << "\",";
-        out << "\"file\":\"" << loc->file << "\",";
+        std::string escapedFilePath = loc->file;
+        std::replace(escapedFilePath.begin(), escapedFilePath.end(), '\\', '/');
+        out << "\"file\":\"" << escapedFilePath << "\",";
         out << "\"line\":" << loc->line << "";
         out << "}";
     }