Rename the "Han Chinese" to "Han"

Han Chinese is not wrong per se but unnecessary precise.
See the forum discussion here: https://wildfiregames.com/forum/topic/51306-thread-for-posting-suggestions-for-alpha-26/page/15/#comment-495849
and the usage of "Han" in an article from the metropilitan museeum: https://www.metmuseum.org/toah/hd/hand/hd_hand.htm

comments by:
@Langbart

accepted by :
@asterix
@Freagarach

Differential revision: https://code.wildfiregames.com/D4659