API encode/decode fixes

[virtulis]

1. Added a number of missing node properties for the API encoder/decoder on both ends.
2. Added the token type for the HeritageClause, as far as I understand the bit usage is arbitrary per kind, so just used the first one.
3. Changed isTypeNode to also return true on type keywords, list copied from KeywordTypeSyntaxKind. These appear as is in parser output, which is probably correct?

All of these were hit mostly by just doing roundtrips of some test code between the parser and emitter via the API and getSynthesizedDeepClone. Probably a bunch more to be found that way.

[virtulis]

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