[whatwg] Adding obsolete elements/attributes to indexes

[Simon Sapin]

Hi,

The HTML spec has an Index section, with tables of all existing 
elements, attributes, and other things. I find this very helpful.

When considering what Servo should implement, I mistakenly concluded 
that <li> elements do not have a 'type' attribute, based on the Index. 
They in fact do, as specified in the Obsolete features section.

That such features are in the spec at all, even though authors "must 
not" use them, probably means that Servo needs to implement them. 
However these features are not mentioned at all outside of the Obsolete 
features section, to it’s not easy to discover that they even exist if 
one does not think of look for Obsolete features specifically.

To help with "discoverability" of obsolete features by implementers, I’d 
like them to be included in the Index section’s tables.

-- 
Simon Sapin