docs: link package-registry names in related-libraries footer (#7)

npm, Maven Central, pkg.go.dev, and pub.dev were bare text; clicking
them led nowhere. Make all the registry labels real hyperlinks for parity
with the PyPI / Packagist / NuGet entries already on the row.

Author: arjunjain

README.md

@@ -194,12 +194,12 @@ offline — no API key required.
 Official Newsdata.io clients across languages and runtimes:
 
 - **Python** — [newsdataapi/python-client](https://github.com/newsdataapi/python-client) ([PyPI](https://pypi.org/project/newsdataapi/))
-- **Node.js** — [newsdataapi/newsdata-nodejs-client](https://github.com/newsdataapi/newsdata-nodejs-client) (npm)
-- **React (hooks)** — [newsdataapi/newsdata-reactjs-client](https://github.com/newsdataapi/newsdata-reactjs-client) (npm)
-- **Java** — [newsdataapi/newsdata-java-sdk](https://github.com/newsdataapi/newsdata-java-sdk) (Maven Central)
+- **Node.js** — [newsdataapi/newsdata-nodejs-client](https://github.com/newsdataapi/newsdata-nodejs-client) ([npm](https://www.npmjs.com/package/newsdata-nodejs-client))
+- **React (hooks)** — [newsdataapi/newsdata-reactjs-client](https://github.com/newsdataapi/newsdata-reactjs-client) ([npm](https://www.npmjs.com/package/newsdataapi))
+- **Java** — [newsdataapi/newsdata-java-sdk](https://github.com/newsdataapi/newsdata-java-sdk) ([Maven Central](https://central.sonatype.com/artifact/io.newsdata/newsdataapi))
 - **.NET** — [newsdataapi/newsdata-dotnet-sdk](https://github.com/newsdataapi/newsdata-dotnet-sdk) ([NuGet](https://www.nuget.org/packages/Newsdata.Api/))
-- **Go** — [newsdataapi/newsdata-go-client](https://github.com/newsdataapi/newsdata-go-client) (Go modules)
-- **Dart / Flutter** — [newsdataapi/newsdata-flutter-client](https://github.com/newsdataapi/newsdata-flutter-client) (pub.dev)
+- **Go** — [newsdataapi/newsdata-go-client](https://github.com/newsdataapi/newsdata-go-client) ([pkg.go.dev](https://pkg.go.dev/github.com/newsdataapi/newsdata-go-client))
+- **Dart / Flutter** — [newsdataapi/newsdata-flutter-client](https://github.com/newsdataapi/newsdata-flutter-client) ([pub.dev](https://pub.dev/packages/newsdataapi))
 - **MCP Server (AI assistants)** — [newsdataapi/newsdata.io-mcp](https://github.com/newsdataapi/newsdata.io-mcp) ([PyPI](https://pypi.org/project/newsdata-mcp/))
 
 Also see [free news datasets](https://github.com/newsdataapi/newsdata.io-free-datasets) for ML / NLP work.