Add export of PredicateTest type

Author: wooorm

index.js

@@ -4,6 +4,11 @@
  * @typedef {import('./lib/index.js').AssertAnything} AssertAnything
  */
 
+/**
+ * @template {import('unist').Node} Kind
+ * @typedef {import('./lib/index.js').PredicateTest<Kind>} PredicateTest
+ */
+
 /**
  * @template {import('unist').Node} Kind
  * @typedef {import('./lib/index.js').TestFunctionPredicate<Kind>} TestFunctionPredicate