Change plain text in sample code to be comments (#26703)
Change plain text in sample code to be comments (#26703)

In the sample CSS code, there were some notes to add some additional explanation on the code. Changed those notes to be code comments so that if a person copies and pastes the code samples then they will not face any errors since the notes are valid comments in code instead of being plain text which can't be interpreted.
jonathanihm/freeCodeCamp,FreeCodeCamp/FreeCodeCamp,jonathanihm/freeCodeCamp,BhaveshSGupta/FreeCodeCamp,raisedadead/FreeCodeCamp,FreeCodeCamp/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,raisedadead/FreeCodeCamp