Format input output to user locale

I've been trying to set the format to user's locale format (the formatted string visible in the input field) to no availability.
The problem seems to be that the `format` parameter expects a format string eg `{{pikaday-input format="MM/DD/YYYY"}}` but it's impossible to find out what the browser's format is currently set.

I would actually expect the output to be processed with `Date.prototype.toLocaleDateString()` by default with the option to customize it using the `format` parameter.

It might be me missing something important. Do you have any suggestions?

Start by tracing how the `format` parameter is handled by the datepicker component and how the formatted string is placed in the input field. Compare that behavior with `Date.prototype.toLocaleDateString()` and determine the expected default and customization behavior, then define tests covering locale output and an explicit `format` value.

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