Update CNS_region for HGG

[jharenza]

What data file(s) does this issue pertain to?

pbta-histologies.tsv

What release are you using?

v18

Put a link to the relevant section of the OpenPBTA-manuscript here.

NA

Put your question or report your issue here.

Cassie Kline had done some internal review of pathology reports to update HGG CNS_regions, and we will capture these in #867 histologies file. See attached review.
CNS_region_review_HGG_CK_update.txt

[kgaonkar6]

closing since this is updated in base histology creation step https://github.com/d3b-center/D3b-codes/blob/6fd75ef9f870172299ab6ce9dd014d0ecf882fb1/OpenPBTA_v19_20210423/review_updates.Rmd