add shared picker dfn

source

@@ -48169,6 +48169,11 @@ interface HTMLInputElement : HTMLElement {
   data-x="attr-input-type-checkbox">Checkbox
   being mutable.
 
+  Some states of the type attribute 
+  data-x="input-support-picker">support a picker, which is a popup that allows the user to
+  choose a value. Which states support a picker is up to
+  the user agent.
+
   The cloning steps for input elements
   must propagate the value, 
   data-x="concept-fe-dirty">dirty value flag
@@ -52636,8 +52641,10 @@ You cannot submit this form when the field is incorrect.
    input.showPicker()
 
    
-    Shows any applicable picker UI for input, so that the user can select a value. (If
-    no picker UI is implemented for the given control, then this method does nothing.)
+    If input does not support a picker,
+    this method does nothing.
+
+    Shows any applicable picker UI for input, so that the user can select a value.
 
     Throws an "InvalidStateError" DOMException if
     input is not mutable.
@@ -74811,8 +74818,8 @@ Demos:
      A select element which is a drop-down box whose drop-down box
      is open.
 
-     An input element which supports a picker popup and whose picker popup is
-     open.
+     An input element which ">supports a
+     picker popup and whose picker popup is