fix typo (#651)

fix typo in readme examples

Author: SangamSwadiK

examples/README.md

@@ -1,7 +1,7 @@
 Example notebooks are stored in `../doc/source/examples/`. 
 
 This directory contains symbolic links to the notebooks, which serve as shortcuts. For example, 
-the `cd_mol.ipynb` notebook can be opened by running `jupyer-notebook examples/cd_mol.ipynb` in 
+the `cd_mol.ipynb` notebook can be opened by running `jupyter-notebook examples/cd_mol.ipynb` in 
 the root directory.
 
 Note: The symbolic links might not work on some Windows versions.