help: escape sequence for `/*`

How'd I escape a C-style comment e.g. `/* hi */`?

```
<Multi_key> <z> <a> : "/* hi */" # outputs nothing
<Multi_key> <z> <b> : "/ * hi */" # outputs "/ * hi*/"
```

I can't figure out what needs escaping here - everything I've tried e.g. `//*`, `/\*`, `/**` hasn't worked