Intent to unship: quotes around the MathML <ms> element

[Frédéric Wang]

As of October 3 I intend to remove support for quotes around the MathML <ms> element, and the corresponding lquote/rquote attributes.

Chromium and WebKit don't implement that feature.

Bug to remove: https://bugzilla.mozilla.org/show_bug.cgi?id=1793387

This is a rarely used MathML element, quotes are not part of MathML Core and not implemented in other browsers and Firefox's implementation has issues (e.g. bugs 1108608 and 787215).

-- 
Frédéric Wang