How do I run an autocomplete $search on multiple fields?

The documentation states that the path needs to be a string and not an array of strings. I just want to confirm that that is in fact the only possibility, and if, in either case, there is a recommended way to do this.

e.g. I want to search (with autocompletion) my movies for the text "hammer" on both the title and the plot

In the current scenario I can implement a search by either title or plot with ease. But If I try to do it for both, making path an array of strings, which is acceptable on other operators, I get an error