docs: Update example in README

Author: razor-x

README.md

@@ -22,7 +22,8 @@ Serialization uses
 which encodes most non-alphanumeric characters.
 
 - The primitive types `string`, `number`, and `bigint` are serialized using `.toString()`.
-- The primitive `boolean` type is serialized using `.toString()` to `'true'` or `'false'`.
+- The primitive `boolean` type is serialized using `.toString()`,
+  e.g., `{ foo: true, bar: false }` serializes to `foo=true&bar=false`.
 - The primitive `null` and `undefined` values are removed,
   e.g., `{ foo: null, bar: undefined, baz: 1 }` serializes to `baz=1`.
 - `Date` objects are detected and serialized using `Date.toISOString()`.