"value_type" aka. Unit beliefs, is named a bit ambiguously

[cppcooper]

df-structures/df.units.xml

Lines 146 to 151 in a04727c

	<enum-type type-name='value_type'>
	<enum-item name='NONE' value='-1'/>
	<enum-item name='LAW'/>
	<enum-item name='LOYALTY'/>
	<enum-item name='FAMILY'/>

It would be nice if this was named similar to the wiki article, if only for the sake of searchability.

edit: as per discord discussion, the game seems to refer to this system as a value system. @Ozzatron arrived on personality_value_type as an alternative to simply value_type