DOES>

Used inside a colon definition that itself uses CREATE, DOES>
transforms that newly created word into a "does cell", that is,
a regular cell (when called, puts the cell's addr on PS), but
right after that, it executes words that appear after the
DOES>.

"does cells" always allocate 4 bytes (2 for the cell, 2 for the
DOES> link) and there is no need for ALLOT in colon definition.

At compile time, colon definition stops processing words when
reaching the DOES>.

Example: ": CONSTANT CREATE HERE @ ! DOES> @ ;"

