sq: bash tab completion is confused when tab-completing at `sq key`

Consider the following bash tab completions:

1. sq <TAB> yields a list of all subcommands and options (including key and keyring)

2. sq k<TAB> automatically fills in sq key and leaves the cursor at the end of key

3. sq key<TAB><TAB> shows nothing, if there are no local files whose names start with key. If one local file named keyfoo exists, it expands to sq keyfoo after the first <TAB>, and if two local files names keyfoo and keybar exist, it lists them both.

4. sq key <TAB><TAB> (note the space after key) shows the sub-sub-commands adopt, attest-certifications, generate, help, etc.

The third item in the list above is clearly wrong. It should instead show the two options key and keyring.