KDoc for private properties are added only when there was no KDoc (also warning)

[petertrr]

This code

class Example(private val foo: Int)

is autofixed into

/**
 * @property foo
 */
class Example(private val foo: Int)

while this

/**
 * KDoc
 */
class Example(private val foo: Int)

doesn't.
The first snippet shouldn't be corrected too.

This is not only about the fixer; the warning is emitted in checking mode too.

diktat versions: 0.1.5