- the context exists for the lifecycle of one card's render,
and caches calls to things like .card() to avoid add-ons needing to
do their own cache management.
- add-ons can optionally add extra data to the context if they need
it across multiple filters
- removed card_will_render. the legacy hook is still available for
now
- card_did_render is now called only once, with both front and back
text
This allows us to add a docstring to .append() so users can see
the names of the arguments that are being passed, and means we
don't have to remember to prepend run_ when calling a hook.
- The front and back are rendered in one call now. If the front
side contains no custom filters, we can bake {{FrontSide}} into the
rear side. If it did contain custom filters, we return the partially
complete rear template instead, and the calling code can inject
the FrontSide in after it has been fully rendered.
- Instead of modifying "cloze" into something like "cq-2", the card
ordinal and whether we're rendering the question or answer are now
passed in to the rendering filters as context.
- The Rust code doesn't need to support filter names split on '-'
anymore.
- Drop the "Show" part of hint descriptions so i18n support can be
deferred.
- Ignore blank filter names caused by user using two colons instead
of one.
- Fixed hint field and text transposition.
