REPL prints empty string when defining rule with ref name

[tsandall]

This is just a minor bug, it looks like the REPL is not rendering the rule name correctly.

(main)torin:~/go/src/github.com/styrainc/concourse-defs$ opa run
OPA 1.1.0-dev (commit 4782cc5721d37d807e60cbedc1a7cc201257eba9, built at 2025-01-21T13:49:47Z)

Run 'help' to see a list of commands and check for updates.

> a.b.c.d if { input.foo }
Rule '' defined in package repl. Type 'show' to see rules.

Specifically in the message that the REPL prints:

Rule '' defined in package repl. Type 'show' to see rules.
     ^^