Update hashmaps3.rs description for clarity

I struggled with this exercise and didn't understand that it was looking for a summary of goals scored/conceded per team, instead of per match.

My goal here is just to clarify the language, essentially saying "the total number of goals the team scored" to indicate that we are looking for a sum.

Updated the exercise description to clarify this point.

Relates loosely to closed issue #1361

Author: evanmiller2112

exercises/11_hashmaps/hashmaps3.rs

@@ -4,10 +4,11 @@
 // the form : "<team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>"
 // Example: England,France,4,2 (England scored 4 goals, France 2).
 //
-// You have to build a scores table containing the name of the team, goals the
-// team scored, and goals the team conceded. One approach to build the scores
-// table is to use a Hashmap. The solution is partially written to use a
-// Hashmap, complete it to pass the test.
+// You have to build a scores table containing the name of the team, the total
+// number of goals the team scored, and the total number of goals the team 
+// conceded. One approach to build the scores table is to use a Hashmap. 
+// The solution is partially written to use a Hashmap, 
+// complete it to pass the test.
 //
 // Make me pass the tests!
 //