set_bmask_cmt

set bitmask comment (only for bitfields)
     enum_id - id of enum
     bmask   - bitmask of the constant
     cmt     - comment
     repeatable - type of comment, 0-regular, 1-repeatable
returns: 1-ok, 0-failed

long set_bmask_cmt(long enum_id, long bmask, string cmt, long repeatable);