"how2 -l cmd change directory" works for me. "how2 -l cmd enable tab completion" still returns nothing, though; I think that's just a query it can't answer. (A quick manual search returned totally unhelpful results, so I wouldn't blame how2 for that...)
how2 -l windows enable tab completion
and got nothing. "PowerShell" and "batch" bring back results, but I am drawing a blank on what to call the Windows Shell (cmd.exe). Thanks!