Link prediction method in documentation is called `recommend` while in the code it's `recommended_vertex`

[Josipmrden]

In documentation we have the correct naming of the link prediction method called "recommend". In the code we have it under "recommended_vertex" and also it is in the blog post https://memgraph.com/blog/building-a-recommendation-system-for-telecommunication-packages-using-graph-neural-networks like that. It should be change to recommend.