docs/make.bat: Save `readme.rst` from being destroyed during `make.bat clean`.
docs/make.bat: Save `readme.rst` from being destroyed during `make.bat clean`.

nanshe-org/nanshe,DudLab/nanshe,jakirkham/nanshe,nanshe-org/nanshe,jakirkham/nanshe,DudLab/nanshe