fix: typecheck Gio.Settings constructor 'settings_schema' parameter.
Closes #418 (closed)
Testing
Used the example script from the issue.
[aiono@aiono-fedora gjs-nix]$ ./result/bin/gjs test.js
(gjs:303720): Gjs-CRITICAL **: 17:32:47.959: JS ERROR: Error: Value of property 'settings_schema' is not of type 'Gio_SettingsSchema'
_init@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:747:23
@test.js:3:18
(gjs:303720): Gjs-CRITICAL **: 17:32:47.959: Script test.js threw an exception