Added 'announce' command to usage.

main.c

@@ -32,6 +32,7 @@ int usage(void)
     printf("request {basedir} {uid} {url}       Requests an object\n");
     printf("actor {basedir} [{uid}] {url}       Requests an actor\n");
     printf("note {basedir} {uid} {text} [files...] Sends a note with optional attachments\n");
+    printf("announce {basedir} {uid} {url}      Announces (boosts) a post\n");
     printf("resetpwd {basedir} {uid}            Resets the password of a user\n");
     printf("ping {basedir} {uid} {actor}        Pings an actor\n");
     printf("webfinger_s {basedir} {uid} {actor} Queries about an actor (@user@host or actor url)\n");