Auto merge of #19509 - jonleighton:remove-input-type-datetime, r=jdm

Remove support for <input type=datetime>

It has been removed from the spec: https://github.com/whatwg/html/issues/336

See also https://github.com/servo/servo/pull/19471#pullrequestreview-80711878

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tests/wpt/metadata/html/semantics/forms/historical.html.ini

@@ -1,8 +1,5 @@
 [historical.html]
   type: testharness
-  [<input type=datetime> should not be supported]
-    expected: FAIL
-
   [<input name=isindex> should not be supported]
     expected: FAIL