Fix mistake in swap command shell completion

Author: nikitabobko

grammar/commands-bnf-grammar.txt

@@ -64,7 +64,7 @@ aerospace -h;
 
     | split [--window-id <window_id>] (horizontal|vertical|opposite) [--window-id <window_id>]
 
-    | swap [--swap-focus|--wrap-around] (left|down|up|right|dfs-next|dfs-prev) [--swap-focus|--wrap-around]
+    | swap [--swap-focus|--wrap-around]... (left|down|up|right|dfs-next|dfs-prev) [--swap-focus|--wrap-around]...
 
     | summon-workspace [--fail-if-noop] <workspace> [--fail-if-noop]