fix: path item $ref rendering (#4381)

* WIP: trigger resolution of Path Item $ref on spec load

* fix(dev-server): don't open localhost in a browser

* preserve key order when merging specJson with specResolvedSubtrees

* remove stray `debugger`

package.json

@@ -19,9 +19,8 @@
     "build-core": "webpack --config webpack-dist.config.js --colors",
     "build-standalone": "webpack --config webpack-dist-standalone.config.js --colors",
     "predev": "npm install",
-    "dev": "npm-run-all --parallel hot-server open-localhost",
+    "dev": "npm-run-all --parallel hot-server",
     "watch": "webpack --config webpack-watch.config.js --watch --progress",
-    "open-localhost": "node -e 'require(\"open\")(\"http://localhost:3200\")'",
     "hot-server": "webpack-dev-server --host 0.0.0.0 --config webpack-hot-dev-server.config.js --inline --hot --progress --content-base dev-helpers/",
     "deps-license": "license-checker --production --csv --out $npm_package_config_deps_check_dir/licenses.csv && license-checker --development --csv --out $npm_package_config_deps_check_dir/licenses-dev.csv",
     "deps-size": "webpack -p --config webpack.check.js --json | webpack-bundle-size-analyzer >| $npm_package_config_deps_check_dir/sizes.txt",