fun createChildWithNewPrefixAndAdditionalIndent(newPrefix: String, additionalIndent: Int): AssertionFormatterMethodObject
Creates an AssertionFormatterMethodObject for kind of a child of the current method object using the given newPrefix and an additionalIndent (the child will typically be used to indent IAssertions one level more).
Technically speaking it means that the child's indentLevel is based on the current method object but increased by the current method object's prefix.length as well as the given additionalIndent.
newPrefix - The new prefix to be used.
additionalIndent - The additional indent which should be added to the current indentLevel next to the
current prefix.length.
Return
The newly created AssertionFormatterMethodObject.