fix pages

{{cookiecutter.repo_name}}/pages/docs/index.md

 # {{cookiecutter.project_name}} Documentation
 
-[{{cookiecutter.project_name}}](https://git-st.inf.tu-dresden.de/jastadd/preprocessors/{{cookiecutter.project_slug}}) is a tool using [JastAdd](http://jastadd.org/).
+[{{cookiecutter.project_name}}]({{cookiecutter.repo_url}}) is a tool using [JastAdd](http://jastadd.org/).
 
 ## The Grammar