fix(#21): ensure multiselect returns values

Author: natemoo-re

.changeset/tender-dingos-guess.md

@@ -0,0 +1,5 @@
+---
+"@clack/core": patch
+---
+
+Fix multiselect returning undefined

packages/core/src/prompts/multi-select.ts

@@ -30,7 +30,9 @@ export default class MultiSelectPrompt<T extends { value: any }> extends Prompt
             }
         }
         super(opts, false);
-        
+        this.once('finalize', () => {
+            this.value = this.selectedValues;
+        })
         this.options = opts.options;
         this.cursor = this.options.findIndex(({ value }) => value === opts.initialValue);
         this.selectedValues = []