Adding more docs to licenses.ts

src/licenses.ts

@@ -3,6 +3,11 @@ import {Change, ChangeSchema} from './schemas'
 /**
  * Loops through a list of changes, filtering and returning the
  * ones that don't conform to the licenses allow/deny lists.
+ *
+ * Keep in mind that we don't let users specify both an allow and a deny
+ * list in their config files, so this code works under the assumption that
+ * one of the two list parameters will be empty. If both lists are provided,
+ * we will ignore the deny list.
  * @param {Change[]} changes The list of changes to filter.
  * @param { { allow?: string[], deny?: string[]}} licenses An object with `allow`/`deny` keys, each containing a list of licenses.
  * @returns {Array<Change} The list of denied changes.