Change spacing to one sentence per line

Author: Elahi Concha

exercises/grade-school/description.md

@@ -13,6 +13,9 @@ In the end, you should be able to:
 - Get a sorted list of all students in all grades.
   Grades should be sorted as 1, 2, 3, etc., and students within a grade should be sorted alphabetically by name.
   - "Who is enrolled in school right now?"
-  - "Let me think. We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2, and Jim in grade 5. So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe, and Jim."
+  - "Let me think. 
+  We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2, and Jim in grade 5.
+  So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe, and Jim."
 
-Note that all our students only have one name (it’s a small town, what do you want?), and each student cannot be added more than once to a grade or the roster. If a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.
+Note that all our students only have one name (it’s a small town, what do you want?), and each student cannot be added more than once to a grade or the roster.
+If a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.