rb: fix qhelp

Author: yoff

ruby/ql/src/queries/performance/CouldBeHoisted.qhelp

@@ -16,7 +16,7 @@ This query identifies situations where an ActiveRecord query execution could be
 <example>
 <p>The following (suboptimal) example code queries the User object in each iteration of the loop:</p>
 <sample src="examples/straight_loop.rb" />
-<p>To improve the performance, we instead query the User object once outside the loop, gathereing all necessary information:
+<p>To improve the performance, we instead query the User object once outside the loop, gathereing all necessary information:</p>
 <sample src="examples/preload.rb" />
 </example>
 </qhelp>