Add attributes to control date display

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It would be helpful if the standard supported attributes to tell the browser which format to use for display of dates. In the absence of such attributes, browsers use whatever locale information is available to for showing the date, making it impossible for developers of web pages to assume that the display will be consistent across all browsers, and thus making it more difficult to provide simple, clear documentation of those web pages. I have customers who would like dates to be displayed using the standard ISO format, to eliminate any possible confusion or ambiguity about which portion of the displayed value represents the month, and which portion represents the day of the month, but standard HTML markup doesn't support that. Introduction of sequence and separator attributes (possibly with different names to anticipate naming conflicts) would make it possible to do what our customers want without relying on convoluted JavaScript code. For example:

<input type="date" sequence="ymd" separator="-">