class Reline::LineEditor

def vi_kill_line_prev(key)

to the beginning of the current line.
GNU Readline:: +unix-line-discard+ (+C-u+) Kill backward from the cursor
cut buffer.
beginning of the edit buffer to the cursor and save it to the
Editline:: +vi-kill-line-prev+ (vi: +Ctrl-U+) Delete the string from the 
def vi_kill_line_prev(key)
te_pointer > 0
e, deleted = byteslice!(@line, 0, @byte_pointer)
e_pointer = 0
l_ring.append(deleted, true)
sor_max = calculate_width(@line)
sor = 0