Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

Fish completion will not work if the command is prefixed with a space.

Steps to reproduce the issue:

1. In fish shell, type <SPACE>podman<SPACE>

2. Press TAB

Describe the results you received:

Fish shows file completion

❯  podman
bspwm_0_0-socket  fcitx-socket-:0  nvimgPYgkx/  tmux-1000/

Describe the results you expected:

Fish shows command completion

❯ podman
attach                                      (Attach to a running container)
auto-update  (Auto update containers according to their auto-update policy)
build               (Build an image using instructions from Containerfiles)
commit                    (Create new image based on the changed container)
…and 51 more rows

Additional information you deem important (e.g. issue happens only occasionally):

Output of podman version:

Version:      2.2.1
API Version:  2.1.0
Go Version:   go1.15.6
Git Commit:   a0d478edea7f775b7ce32f8eb1a01e75374486cb
Built:        Thu Dec 24 19:42:33 2020
OS/Arch:      linux/amd64

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide?

Yes

Additional environment details (AWS, VirtualBox, physical, etc.):

❯ fish --version
fish, version 3.1.2