Change ge element analogue to g<M-e> for symmetry
Reword wrap <Plug> names

sexp_list_wrap_round_head vs
sexp_round_head_wrap_list

Sounds more like an action.
Rename text object <Plug> names from verb -> noun

The text objects are only available in visual and operator-pending
modes, so it is misleading to have the action "select" in the names.
Note about <Plug> renames and forward stability
Use head|tail instead of first|last in sexp_emit_*