Expose `auto_suggest.resume_hinting`, fix resume on backspace (#13994) This is a pre-requisite of #13992 but the shortcut is disabled by default by `never` filter. The idea here is that this could be merged as-is (ideally after rebasing on top of #13991) to allow user testing. Once this is in, users can emulate part of the behaviour proposed in #13992 with the following snippet: ```python custom_shortcuts = [ { "command": "IPython:auto_suggest.resume_hinting", "new_keys": ["right"], "new_filter": "default_buffer_focused & ((vi_insert_mode & ebivim) | emacs_insert_mode)" } ] %config TerminalInteractiveShell.shortcuts = custom_shortcuts ```