expr: fix listel/hashel accessors

the listel/hashel is not a lick, just call the value with the index to get the value.
add listel.pl test
simplify scalar !'[' !'{'
use p2; reorder static strings

use is not properly implemented yet:
- special case p2 (syntax mode) not scoped yet (create block)
- no push to begin_av, require, import args yet