Wrong unichr docstring in 2.7

[jmfauth]

Short comments:

1) I'm aware Python can be built in "ucs2" or "ucs4" mode. It remains
that the unichr doc string does not seem correct.

2) 0x0 versus 0
Do not take this too seriously. Sure the value of 0x0 and 0 are equal,
but the "unit" sounds strange.
Eg. If a is a length, I would not express a as beeing
0 mm <= a <= 999 m  (or 0 in <= a <= 999 ft) but 0 m <= a <= 999 m .
I agree a notation like 0x0000 <= i <= 0xffff is even the best.

3) Of course, the Python 3 behaviour (chr() instead of unichr()) is
correct.

jmf