checker: disallow Result callbacks functions like map/filter/all/any

[Delta456]

Fixes #21049

[spytheman]

.map(f()!) should be allowed, since f()! is sugar for f() or { return err }, which is well defined.

[spytheman]

The checker however should check whether f()! returns a valid type .
In other words, it should allow:
.map( f1()! ), for fn f1() !Type {
... but it should not allow:
.map( f2()! ) for fn f2() ! {

[Delta456]

The checker however should check whether f()! returns a valid type . In other words, it should allow: .map( f1()! ), for fn f1() !Type { ... but it should not allow: .map( f2()! ) for fn f2() ! {

Fair

[spytheman]

Excellent work.
Sorry for the delay.

[ttytm]

Wanted to try to utilize it instead of an or block, I'm still running into a builder error here:

v/vlib/x/json2/decoder.v

Lines 292 to 294 in bccf660

	// NOTE: Using `!` on `to_time()` inside the array method causes a builder error - 2024/04/01.
	[]time.Time { typ.$(field.name) = arr.map(it.to_time() or { time.Time{} }) }
	[]?time.Time { typ.$(field.name) = arr.map(?time.Time(it.to_time() or { time.Time{} })) }