Infer pcall's own return when the called function has none

[RomanSpector]

pcall returns false plus the error value when the call fails, and the meta declares that second result as any. For a function declared as fun() it came out as unknown instead:

---@type fun()
local task

local ok, err = pcall(task)   -- err: unknown, expected any

The compiler takes the called function's return under the same index and stops there. getReturn always yields a node — an empty one when there is nothing to take — so the if node then guard passed even when the function returns nothing, and that empty node became the result.

An empty node is no longer accepted as an answer: compilation falls through to pcall's own declaration. The same applies to xpcall, where the message handler's result takes the place of the missing return.

Functions that do return a value are unaffected — the existing tests cover that, and two new ones cover the case above.

[gemini-code-assist]

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