decoder/schema: Report completed attributes with Kind per constraint

[radeksimko]

Context

Currently when we complete any attribute, either 1st class

or within an Object (#203)

TODO

or key within a Map (#199)

the reported Kind is always broad "attribute", regardless of the attribute's constraint/type (e.g. string, number, ...).

Proposal

Consider replacing the broad "attribute" kind with the kind relevant to the constraint type, as available in

hcl-lang/lang/candidate.go

Lines 16 to 25 in 91de83d

	BoolCandidateKind
	KeywordCandidateKind
	ListCandidateKind
	MapCandidateKind
	NumberCandidateKind
	ObjectCandidateKind
	SetCandidateKind
	StringCandidateKind
	TupleCandidateKind
	TraversalCandidateKind

This could provide more helpful completion experience where the user can more quickly do "eye scan" through the icons and visually filter by types.

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Notes

For consistency we may want to do something similar for blocks, which can also be of different types, although these would be just one of the following:

• object
• list
• set
• map