use yaml instead of json for object detector docs

docs/plugins/js-yaml-loader.js

@@ -0,0 +1,9 @@
+const yaml = require("js-yaml");
+
+// Webpack loader that compiles a YAML file into a default-exported JS object,
+// so docs data can be authored in YAML (block scalars, no quote/newline
+// escaping) but imported exactly like the JSON it replaces.
+module.exports = function (source) {
+  const data = yaml.load(source);
+  return `export default ${JSON.stringify(data)};`;
+};