Currently it doesn't work as expected, namely gets stuck on delimiter and caret is moved before the delimiter.
Unnecessary more robust than Windows, which feels like doesn't do any checks at all.
EDIT1: v2: return length in `WB_RIGHT` if its bigger than default return value of 0 on invalid values
EDIT2: v3: don't test `WB_ISDELIMITER` with out of bounds indices, Windows doesn't check them and does out of bounds reads
-- v5: comctl32: Fix PathWordBreakProc.