text: Title: Typo in NeighborLoader
  Body: ### 📚 Describe the documentation issue
  
  There is a small typo in the docs (https://github.com/pyg-team/pytorch_geometric/blob/f5c829344517c823c24abb08ce2fc7cf00ff29f7/torch_geometric/loader/neighbor_loader.py#L17)
  
  ### Suggest a potential alternative/fix
  
  It should say: `    More specifically, :obj:`num_neighbors` denotes how many neighbors are`