15.11.2: Edit introduces contradiction

The second bullet of this clause has added "or a type derived from it":

> • A unary `++` or `--` operator shall take a single parameter of type `T` or `T?` and shall return that same type or a type derived from it.

This contradicts $13.8.6 which states:

> The operand of a prefix increment or decrement operation shall be an expression classified as a variable, a property access, or an indexer access. The result of the operation is a value of the same type as the operand.

_Note this isn't saying that the type of the variable and the type of the operator match, text later in that clause allows for value of variable type -> convert to value of operator type -> operation producing value of operator type -> convert to value of variable type._

_Note this restriction does not appear to apply to other operators, e.g. unary or binary `+` can take and return different types._

So we have a contradiction, which is right? I'll go with the Standard being right unless someone presents the contra-case.

Proposal: reject the addition of "or a type derived from it" reverting to the Standard text.