Change the placeholder string for search to 'Search API Docs' (#1813)

* Change the placeholder string for search to 'Search API Docs'

* Update docs

Author: gspencergoog

lib/resources/script.js

@@ -121,7 +121,7 @@ function initSearch(name) {
     }
 
     $('#' + name).prop('disabled', false);
-    $('#' + name).prop('placeholder', 'Search');
+    $('#' + name).prop('placeholder', 'Search API Docs');
     $(document).keypress(function(event) {
       if (event.which == 47 /* / */) {
         event.preventDefault();