Fix: fix two show-stopper bugs

crates/forth/src/vm.rs

@@ -1778,6 +1778,9 @@ fn emit_output(
     }
 
     for (i, (k, v)) in params.iter().enumerate() {
+        if v.is_empty() {
+            continue;
+        }
         if !out.ends_with('/') {
             out.push('/');
         }