Rename a node's name oldName or the numth node number in a phrase aPhrase with a new name newName.
None = renamenode(aPhrase, oldName, newName)
aPhrase - type: phrase
oldName - type: str
newName - type: str
None - renamenode(aPhrase, number, newName)
aPhrase - type: phrase
number - type: int
newName - type: str