Fix #6: Make advanced filtering reachable from the TUI

docs/user-guide.md

@@ -29,6 +29,8 @@ The application opens in Read-only Mode. In this mode you can:
 - select a Host Entry and inspect all of its hostnames, comment, state, and DNS
   details;
 - search by hostname, IP address, or comment;
+- use `Ctrl+F` to combine status, entry-type, DNS-resolution, and search
+  filters;
 - sort by IP address or Canonical Hostname;
 - show or hide Default Entries from the configuration screen; and
 - reload `/etc/hosts` from disk.
@@ -221,6 +223,7 @@ continually retrying it.
 | `i` | Sort by IP address |
 | `h` | Sort by Canonical Hostname |
 | `Ctrl+R` | Reload `/etc/hosts` |
+| `Ctrl+F` | Open advanced filters |
 | `c` | Open configuration |
 | `?` | Show help |
 | `q` or `Ctrl+C` | Quit |