Fix typos.

lib/middleware-common/src/metering.rs

@@ -247,7 +247,7 @@ mod tests {
         // verify it returns the correct value
         assert_eq!(value, 7);
 
-        // verify is uses the correct number of points
+        // verify it used the correct number of points
         assert_eq!(get_points_used(&instance), 74);
     }
 
@@ -276,7 +276,7 @@ mod tests {
             _ => unreachable!(),
         }
 
-        // verify is uses the correct number of points
+        // verify it used the correct number of points
         assert_eq!(get_points_used(&instance), 109); // Used points will be slightly more than `limit` because of the way we do gas checking.
     }