Revert "[FIX] stock_picking_wave: removed obsolete many2many widget from stock_picking_wave_view"

This reverts commit 436bbb0a48ff866925fe0a3987928ab554bc3c6d.

The many2many widget is usefull, as it allows to select an existing picking instead of creating a new one when clicking add an item from the list
[DOC] web: search view: extra info about key events handling

Complements bde1a4432fef4cb2f5fe8ab600e72ab5b8b4830d