Reorder Table Tokens properties

[calculuschild]

Working on some custome extensions, I've noticed that Tables seem to be the only token with an odd use of it's tokens parameter. Instead of being an array of tokens, it's instead an object which then contains two token arrays (header and cells). This means we have an odd special case that we have to handle in walktokens for example, and becomes confusing when writing an extension.

I think it would make sense to reorder these properties to follow the format of other tokens to change

tokens = {
  header : [ ],
  cells : [ ]
}

into

header.tokens = [ ];
cells.tokens = [ ];

This better follows the convention of other similar tokens with "sub-tokens" (e.g. Lists contain list items, which then contain tokens, rather than the list having a tokens object containing all the items). Lists are also a weird special case, but we might as well handle both special cases in the same way, and enforce that at least in our implementation, tokens always means an array of tokens.

This wouldn't change functionality, but just provide consistency between tokens.

Changes the token signature of Tables so maybe we can squeeze into version 3.0?

[UziTech]

I think I would be ok with it. So tokens is always just an array of tokens.

[calculuschild]

Right. We are on the same page then. 👍

[calculuschild]

Fixed by #2166