doc: add options documentation to Stream.finished()

When originally implemented it was missed that Stream.finished() has
an optional options object. This adds the docs to those.

doc/api/stream.md

@@ -1294,12 +1294,21 @@ implementors should not override this method, but instead implement
 [`readable._destroy()`][readable-_destroy].
 The default implementation of `_destroy()` for `Transform` also emit `'close'`.
 
-### stream.finished(stream, callback)
+### stream.finished(stream[, options], callback)
 <!-- YAML
 added: v10.0.0
 -->
 
 * `stream` {Stream} A readable and/or writable stream.
+* `options` {Object}
+  * `error` {boolean} If set to `false` a call to emit('error', err) is not
+    treated finished. **Default**: `true`.
+  * `readable` {boolean} When set to `false` the callback will be called after
+    the stream ended but the stream might still be readable. **Default**:
+    `true`.
+  * `writable` {boolean} When set to `false` the callback will be called after
+    the stream ended but the stream might still be writable. **Default**:
+    `true`.
 * `callback` {Function} A callback function that takes an optional error
   argument.