better error message

src/basics.php

@@ -161,7 +161,7 @@ if (!function_exists('breakpoint')) {
             return 'extract(\Psy\Shell::debug(get_defined_vars(), isset($this) ? $this : null));';
         }
         trigger_error(
-            "psy/psysh must be loaded and you should be in CLI to use the breakpoint method",
+            "psy/psysh must be installed and you must be in a CLI environment to use the breakpoint function",
             E_USER_WARNING
         );
     }