CastToNullableType: highlights too much

[TWiStErRob]

Expected Behavior

Highlight either the as keyword or the nullable type, maybe even just the question-mark.

Observed Behavior

Whole expression on the left of the cast is highlighted.

Steps to Reproduce

Any expression really, but it shows most when the casted thing is a chain of functional code

listOf("fieldName").map {
	// very long code
	String::class.java.getDeclaredField(it).get(null)
}.first() as String?

Context

Pretty much the same as #5316, but a different rule.

Your Environment

• Version of detekt used: 1.21.0