fix that jank hack

docs/assets/css/bootstrap.css

@@ -565,7 +565,9 @@ input[type="image"], input[type="checkbox"], input[type="radio"] {
   line-height: normal;
   border: 0;
   cursor: pointer;
-  border-radius: 0 \0/;
+  -webkit-border-radius: 0;
+  -moz-border-radius: 0;
+  border-radius: 0;
 }
 input[type="file"] {
   padding: initial;

less/forms.less

@@ -86,7 +86,7 @@ input[type="radio"] {
   line-height: normal;
   border: 0;
   cursor: pointer;
-  border-radius: 0 e("\0/"); // Nuke border-radius for IE9 only
+  .border-radius(0);
 }
 
 // Reset the file input to browser defaults