Allow heading/title enumeration values in other numberings

[fwkoch]

Currently, you may specify a page-level enumerator, e.g. something like A.%s which will make all numberings on the page A.1 instead of 1.

You may also specify enumerators directly on figures to set a specific value.

However, there is no way to tie page or heading enumeration into other enumerators, so for example I cannot specify I want a figure enumerator to be 1.2.3 where 1.2 is the current heading level and 3 is the figure number.

I think this can be improved in the enumerator templating level, alongside {name}, %s, and {subEnumerator}, such as {h1} or {title}. There's also some strangeness with numbering template vs enumerator which I suspect will require some ironing out... (i.e. I believe the change I suggested will allow cross-references to a figure to display as fig {title}.{h1}.{number}, but the actual enumerator in the figure caption will still just be Figure {number}...)