docs: add JSDoc headers to all externally exported store functions

src/store/tax/create.js

@@ -1,6 +1,17 @@
 import { CREATE } from '../../sql/tax.js';
 import request from '../request.js';
 
+/**
+ * Creates a new tax rate.
+ *
+ * @param {object} pool - The mssql connection pool.
+ * @returns {Function} An async function that creates a tax rate.
+ *
+ * @example
+ * const fn = create(pool);
+ * const id = await fn(19);
+ * // => 1
+ */
 export default function create(pool) {
   return async (rate, tx) => {
     const result = await request(pool, tx)