Merge pull request #352 from paulirish/typolets

fix grammar typo: let => lets. fixes #230

planscore/website/templates/plan.html

@@ -142,7 +142,7 @@ <h3>Mean-Median Difference</h3>
         <li class="col-md-4 col-md-push-4">
             <h4>Sensitivity Testing</h4>
             <p>
-                Sensitivity testing shows us a plan’s expected efficiency gap given a range of possible vote swings. It let us evaluate the durability of a plan’s skew.
+                Sensitivity testing shows us a plan’s expected efficiency gap given a range of possible vote swings. It lets us evaluate the durability of a plan’s skew.
             </p>
         </li>
         <li class="col-md-4 col-md-pull-4">