1. Support `/` and `?` to search. `N` and `Shift+N` to find next/previous
occurence.
2. `Ctrl+N` and `Ctrl+Shift+N` to navigate through the command history.
3. `:nohlsearch` or `<leader><space>` to clear search highlight.
4. `#` and `*` to search current word under cursor.
- `[[`: jump to previous title;
- `]]`: jump to next title;
- `[]`: jump to previous title at the same level;
- `][`: jump to next title at the same level;
- `[{`: jump to previous title at a higher level;
- `]}`: jump to next title at a higher level;
1. Refine VUpdater to compare versions with different sections, such as
1.2.3 or 1.2;
2. Update shortcuts help;
3. Fix bug with autoindent and autolist.
