Update app/scripts/migrations/190.ts

Co-authored-by: Copilot <[email protected]>

Author: davidmurdoch

app/scripts/migrations/190.ts

@@ -3,6 +3,16 @@ import type { Migrate } from './types';
 
 export const version = 190;
 
+/**
+ * Migration that removes `null` seedPhrase values from the persisted state.
+ *
+ * If the `seedPhrase` property exists on the data object and its value is
+ * `null`, this migration deletes the property and records `seedPhrase` in
+ * the set of changed keys.
+ *
+ * @param versionedData - The versioned data object to migrate.
+ * @param changedKeys - A set used to record keys that were modified.
+ */
 export const migrate = (async (versionedData, changedKeys) => {
   versionedData.meta.version = version;