update explanatory comment about iOS date/time inputs bug

Per:
* http://jsbin.com/purer/2/edit
* 6e8aa78384/README.md (ios-temporal-input-line-height)
Thanks @mdo <3

[skip sauce] [skip validator]

less/forms.less

@@ -165,9 +165,11 @@ input[type="search"] {
 }
 
 
-// Special styles for iOS date input
+// Special styles for iOS temporal inputs
 //
-// In Mobile Safari, date inputs require a pixel line-height that matches the
+// In Mobile Safari, setting `display: block` on temporal inputs causes the
+// text within the input to become vertically misaligned.
+// As a workaround, we set a pixel line-height that matches the
 // given height of the input. Since this fucks up everything else, we have to
 // appropriately reset it for Internet Explorer and the size variations.