Fix Jurchen

[xrotwang]

First, we need to move the datapoints for every feature value under
Jurchen, except for the
datapoint for 9A, to Nanai. The datapoint for 9A
will remain as the only datapoint for Jurchen. The only reference for
Jurchen will be the Pevnov reference.

Second, the reference

Hang, Yanchang and Xi, Hang and Shuyan, Ai. 1989. The Hezhen Language. Lin University Press.

should be changed to

Zhang, Xi and Tai, Shu-yen and Zhang, Yanchang, 1989. The Hezhen Language: Ho-che-yū. [Chʿang-chʿun shih]: Jilin University Press.

and this reference is the reference for the datapoints being moved from
Jurchen to Nanai.