Improve record completions

[kerams]

Continuation of #12351, deals with 2 specific cases, which should now fully cover #5519.

No completions in an incomplete record declaration stub.

type A = {
    $
}

No completions when the caret is within a record declaration, but outside of all fields.

type A = {
    Field: string
    $
}

[auduchinok]

No completions when the caret is within a record declaration, but outside of all fields.

@kerams Just in case, could you check that it doesn't break completion for compound type usages, when another type name is written after an existing field?

type Record =
    { Field: int {caret} // completion should be allowed here
    }

type Record =
    { Field: int ->
                 {caret} // completion should be allowed here
    }

[kerams]

If you don't type anything and place the caret there, you won't see any completions in your 2 cases with Ctrl-space. However, when you type the first letter, the position is immediately recognized as part of the preceding field type declaration, and Intellisense pops up automatically (with type-like suggestions only, thanks to the previous PR).

In the second case, because of the arrow it's apparent that a type is needed, so you technically could expect to get Intellisense without typing, but I don't think it's that big of a deal. To me it's a bit of an edge case and detecting it might be somewhat complicated (type A = { Field: int -> {caret} } is reported as containing no fields.).

[baronfel]

Nice change!