Tab completion following ::: delimiter encounters error

[rkben]

Reproduce:

# mise.toml
[tasks.a]
run = """
echo task a
"""

[tasks.b]
run = """
echo task b
"""

rkb@mango:~/t$ mise r <TAB>
a  b  
rkb@mango:~/t$ mise r a ::: <VIGOROUS TABBING OCCURS>
Error:   × unexpected word: :::

Edit: Just remembered mise uses usage, let me know if I should close this and open an issue there.