Add the missing help output for new command: client capa redirect (#1025)

Update client help output message for new command: client capa redirect

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Signed-off-by: hwware <wen.hui.ware@gmail.com>
Signed-off-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>

src/networking.c

@@ -3485,6 +3485,10 @@ void clientCommand(client *c) {
         const char *help[] = {
 "CACHING (YES|NO)",
 "    Enable/disable tracking of the keys for next command in OPTIN/OPTOUT modes.",
+"CAPA <option> [options...]",
+"    The client claims its some capability options. Options are:",
+"    * REDIRECT",
+"      The client can handle redirection during primary and replica failover in standalone mode.",
 "GETREDIR",
 "    Return the client ID we are redirecting to when tracking is enabled.",
 "GETNAME",