Improve wording

src/content/chapter2_flow_control/lesson06_tail_calls/en.html

@@ -6,8 +6,8 @@
 </p>
 <p>
   To avoid this problem Gleam supports <em>tail call optimisation</em>, which
-  allows the compiler to reuse the stack frame for the current function if a
-  function call is the last thing the function does, removing the memory cost.
+  allows the stack frame for the current function to be reused if a function
+  call is the last thing the function does, removing the memory cost.
 </p>
 
 <p>