Functional types in the receiver position need to be parenthesized

[globsterg]

Describe the bug

Due to Kotlin's precedence rules, to define an extension function on a functional type, you must wrap the functional type with parentheses:

public fun ((Int) -> Int).call(argument: Int): Int = this(argument)

Without the parentheses, the compiler marks this code as erroneous:

public fun (Int) -> Int.call(argument: Int): Int = this(argument)
// Compiler error: "Function declaration must have a name"

When generating documentation for the correct call definition, Dokka omits the parentheses, producing incorrect syntax.

I do not know if there are other cases in Kotlin where the type must be parenthesized for the syntax to be correct, so I didn't check them. The maintainers are in a better position to do this.

Expected behaviour

I expect the declarations produced by Dokka to be syntactically correct.

Screenshots

To Reproduce

In kotlinx.coroutines's rendered documentation: https://kotlinlang.org/api/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.intrinsics/start-coroutine-cancellable.html