对于CJK使用ngram设置len=2 不生效

Feature Requests
1

“N-gram lengths for N-gram indexing. Optional, default is 0 (disable n-gram indexing). Known values are 0 and 1.“，我想使用ngram=2,如何设置，目前我设置=2不生效
使用manticoreseach 6.2.12