DOC: Added plt.show() at the end of each necessary block (pandas-dev#45772)

Reworded and moved title to the top of the page

Author: ehallam

doc/source/getting_started/intro_tutorials/04_plotting.rst

@@ -198,8 +198,9 @@ I want to further customize, extend or save the resulting plot.
 
 .. ipython:: python
    :suppress:
-   
+
    import os
+
    os.remove("no2_concentrations.png")
 
 .. raw:: html