fixed pandas/io/formats/printing.py formatting: replaced %/{}.format …
Updated pandas/io/formats/printing.py formatting.  Replaced % and {}.format() examples to python3 formatting. Ran tests and they passed.  

ref [#29886](https://github.com/pandas-dev/pandas/issues/29886) and [#29547](https://github.com/pandas-dev/pandas/issues/29547).
Thanks @AncientRickles 