t.p.deprecate docs should show indeterminate versions

[twm]

The deprecation docs use concrete version numbers, as in this example:

@deprecated(Version("Twisted", 8, 0, 0))
def badAPI(self, first, second):
    '''
    Docstring for badAPI.
    '''
    ...

They should use indeterminate versions instead, since that's what authors should actually write:

@deprecated(Version("Twisted", "NEXT", 0, 0))
def badAPI(self, first, second):
    '''
    Docstring for badAPI.
    '''
    ...