Fixes #484 typo from regexp replace causing placeholder not to exist for input

src/elements/input.less

@@ -83,10 +83,10 @@
 ---------------------*/
 
 /* browsers require these rules separate */
-.ui.input::-web inputkit-input-placeholder {
+.ui.input::-webkit-input-placeholder {
   color: #BBBBBB;
 }
-.ui.input::-moz input-placeholder {
+.ui.input::-moz-placeholder {
   color: #BBBBBB;
 }