new arg to filter by subclass ref

[tintinthong]

Purpose of this PR is to enable spec to choose linkedExamples that link by type

API change

• <@fields @subclassType={{ref}} />. This means users can control the linksTo and linksToMany editor via this arg. It will only work if you pass in a ref which is indeed a subclass of the type. Otherwise, it defaults to original behaviour
• I named it subclassType as the arg @lukemelia different from here https://discord.com/channels/584043165066199050/900021750367129641/1334556182001483826 bcos, I think its wrong to overwrite the field entirely. Now the api works st, you only pass the ref that way @fields.author is still true to the type of author but you can for example, <@fields.author @subclassType=bigAuthorRef>. The issue with adding another filter to the every = [ ] in the card chooser is that the index never supports 2 types so we always have to commit to one

[github-actions]

Host Test Results

    1 files  ±0      1 suites  ±0   23m 37s ⏱️ -1s
757 tests +3  755 ✔️ +3  2 💤 ±0  0 ❌ ±0 
762 runs  +3  760 ✔️ +3  2 💤 ±0  0 ❌ ±0 

Results for commit 9a66cd6. ± Comparison against base commit 28a5621.

♻️ This comment has been updated with latest results.

[burieberry]

This is all good, but I think it would be fine to make an exception and not check isInsideAncestorChain when the type we're comparing to is the base carddef. isInsideAncestorChain will end up loading all the cards in the ancestor chain when we already know that all card subtypes descend from card def. In that case, you can just confirm via isCardDef for the subtype if we're not sure if the type is a card.

[burieberry]

Alternatively, you can only call this function if a subclassType arg was provided

[burieberry]

Actually do you even need to check if the type is the base CardDef? We know that all cards descend from it, so maybe in that case you can skip loading the whole chain and just use the provided subtype.