Update README.md

Author: stephengruppetta

how-to-drop-null-values-in-pandas/README.md

@@ -1,6 +1,6 @@
-The materials contained in this download are designed to complement the RealPython tutorial [How to Drop Null Values in pandas](https://realpython.com/how-to-drop-null-values-in-pandas/).
+The materials contained in this download are designed to complement the Real Python tutorial [How to Drop Null Values in pandas](https://realpython.com/how-to-drop-null-values-in-pandas/).
 
-You should create a new folder named pandas_nulls on your computer and place each file inside it. You may also consider creating a [Python virtual environment](https://realpython.com/python-virtual-environments-a-primer/) within this folder.
+You should create a new folder named `pandas_nulls` on your computer and place each file inside it. You may also consider creating a [Python virtual environment](https://realpython.com/python-virtual-environments-a-primer/) within this folder.
 
 Your download bundle contains the following four files. The first three files contain the code from different tutorial sections, while the fourth contains the solutions to the exercise.
 
@@ -13,4 +13,3 @@ There are also two data files containing the data used throughout the tutorial:
 
 `sales_data_with_missing_values.csv`
 `grades.csv`
-