Avoid contraction

wiki/src/about/staging/about.html

@@ -520,7 +520,7 @@ P7: [DONE] verify-tree.png Says that he doesn't have the skills to verify himsel
   <h2>Top security for free</h2>
 
   <p class="big">Nobody should have to pay to be safe while using a computer.
-  That's why we are giving out Tails for free and try to make it easy to use by
+  That is why we are giving out Tails for free and try to make it easy to use by
   anybody.</p>
 
   <p class="big">We are a nonprofit and an open community.</p>