appops: Update checkOp docs

checkOp (non-raw) actually does evaluate fgdness in most cases, and a
previous change adds package validation functionality. Update the docs
to reflect this.

Test: comment only
Flag: EXEMPT DOCS_ONLY
Bug: 294609684
Change-Id: I2f08ede6f1a05061688757dc0f26bb51770ce46d
1 file changed