Improve redis-cli help. When help command, we only match command (#8879)
Improve redis-cli help. When help command, we only match command (#8879)

prefix args not all args. So when we help commands with subcommands,
all subcommands will be output.
oranagra/redis,PKRoma/redis,oranagra/redis,antirez/redis,soloestoy/redis,ofirluzon/redis,yossigo/redis,antirez/redis,PKRoma/redis,neomantra/redis,soloestoy/redis,PKRoma/redis,oranagra/redis,neomantra/redis,neomantra/redis,ofirluzon/redis,ofirluzon/redis,yossigo/redis,yossigo/redis,soloestoy/redis,neomantra/redis,charsyam/redis,charsyam/redis,neomantra/redis,charsyam/redis,antirez/redis,ofirluzon/redis,charsyam/redis,yossigo/redis,oranagra/redis,PKRoma/redis,antirez/redis,PKRoma/redis,ofirluzon/redis,charsyam/redis,yossigo/redis,soloestoy/redis,soloestoy/redis,oranagra/redis