Suggested small fixes for the Unix Shell Loops lesson 

For my final lesson to become a SWC instructor, I reviewed the unix shell loops lesson and am suggesting two small fixes. The first, is simply to clarify the explanation of the example of why loops are sometimes more useful than wildcards for repeating commands. The second is an addition to the first excercise at the end of the lesson. I think the point of the lesson was to reinforce the difference between using wildcards within for loops versus using $variable_name. Only an example of what happens if you use a wild-card is given. I added an example of using $variable_name so that the learners can clearly examine the differences between these two outputs.