Add alt-backspace, alt-<, alt->, ctrl-j to insert mode (#1441)

* add alt-backspace keymap to delete word backward

* add more useful keymap

* map to correct command

* add C-j to insert_newline

helix-term/src/keymap.rs

@@ -751,8 +751,10 @@ impl Default for Keymaps {
             "del" => delete_char_forward,
             "C-d" => delete_char_forward,
             "ret" => insert_newline,
+            "C-j" => insert_newline,
             "tab" => insert_tab,
             "C-w" => delete_word_backward,
+            "A-backspace" => delete_word_backward,
             "A-d" => delete_word_forward,
 
             "left" => move_char_left,
@@ -767,6 +769,8 @@ impl Default for Keymaps {
             "A-left" => move_prev_word_end,
             "A-f" => move_next_word_start,
             "A-right" => move_next_word_start,
+            "A-<" => goto_file_start,
+            "A->" => goto_file_end,
             "pageup" => page_up,
             "pagedown" => page_down,
             "home" => goto_line_start,