Link fix (#5390)

README.md

@@ -222,7 +222,7 @@ _Libraries for building actor-based programs._
 
 _Libraries for building programs that leverage AI._
 
-- [fun](gitlab.com/tozd/go/fun) - The simplest but powerful way to use large language models (LLMs) in Go.
+- [fun](https://gitlab.com/tozd/go/fun) - The simplest but powerful way to use large language models (LLMs) in Go.
 - [langchaingo](https://github.com/tmc/langchaingo) - LangChainGo is a framework for developing applications powered by language models.
 - [LocalAI](https://github.com/mudler/LocalAI) - Open Source OpenAI alternative, self-host AI models.
 - [Ollama](https://github.com/jmorganca/ollama) - Run large language models locally.