fix broken link for /about/visas/

src/about/opportunity-grants.html

@@ -68,7 +68,7 @@ <h3 id="is-there-anything-i-should-know-if-i-am-traveling-into-the-us-from-anoth
 
     <p>If you are traveling into the United States, we strongly encourage you to wait to purchase airfare or book a hotel room until after your visa has been accepted.</p>
 
-    <p>Find out more details and get your invitation letter at our <a href="/visas/">Visa information page</a>.</p>
+    <p>Find out more details and get your invitation letter at our <a href="/about/visas/">Visa information page</a>.</p>
 
     <h3 id="what-if-there-is-an-emergency-and-i-cannot-attend">What if there is an emergency and I cannot attend?</h3>