Complete the git clone/submodule command in README
Complete the git clone/submodule command in README

bbcmicrobit/PythonEditor,jamesblissett/PythonEditor,jamesblissett/PythonEditor,bbcmicrobit/PythonEditor,bbcmicrobit/PythonEditor,jamesblissett/PythonEditor,bbcmicrobit/PythonEditor