The `--stats-only` option does not have tab-completion

[Douglas Thor]

Summary

The --stats-only option does not have tab-completion.

Steps to reproduce:

1. Type ag --stat<TAB>

Expected Result

$ ag --stat<TAB>
--stata  --stats  --stats-only

Actual Result

$ ag --stat<TAB>
--stata  --stats

Version info:

$ ag --version
ag version 2.2.0

Features:
  +jit +lzma +zlib
$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux rodete
Release:        rodete
Codename:       rodete
$ hostnamectl
 Static hostname: dthor-<redated>
       Icon name: computer-vm
         Chassis: vm
      Machine ID: fdac47<redacted>
         Boot ID: 1b76f1<redacted>
  Virtualization: kvm
Operating System: Debian GNU/Linux rodete
          Kernel: Linux 5.17.11-1rodete2-amd64
    Architecture: x86-64
 Hardware Vendor: Google
  Hardware Model: Google Compute Engine

[Douglas Thor]

I have essentially no experience with C but am willing to help out if someone can point me in the right direction.