> Before applying, consider adding back the part of the docs with the '1 +
> floor(...' definition.

My only (minor) objection to this definition is that a straight Python
translation of it doesn't work, thanks to roundoff error and
the limited precision of floating-point:

>>> from math import floor, log
>>> n = 2**101
>>> n.bit_length()
102
>>> 1 + floor(log(n)/log(2))
101.0
>>> n = 2**80-1
>>> n.bit_length()
80
>>> 1 + floor(log(n)/log(2))
81.0

But as you say, it provides another perspective;  I'm fine with
putting it back in.