Fix FT.SEARCH LIMIT option argument parsing

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

src/cmd.rs

@@ -986,7 +986,7 @@ impl Cmd {
                             while i < cmd.len() {
                                 match cmd[i].to_uppercase().as_str() {
                                     "FILTER" => {
-                                        if i + 3 >= cmd.len() {
+                                        if i + 2 >= cmd.len() {
                                             return Err(DBError(
                                                 "ERR FILTER requires field and value".to_string(),
                                             ));