Bug 1653448 [wpt PR 24642] - Update interfaces/appmanifest.idl, a=testonly

Automatic update from web-platform-tests
Update interfaces/appmanifest.idl (#24642)

Source: https://github.com/tidoust/reffy-reports/blob/0b567ba/ed/idl/appmanifest.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/708988000
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wpt-commits: 5643d1b704e364c55de0cf1221ec738626cb54c5
wpt-pr: 24642

testing/web-platform/tests/interfaces/appmanifest.idl

@@ -8,7 +8,11 @@ dictionary WebAppManifest {
    DOMString lang;
    USVString name;
    USVString short_name;
+   USVString description;
    sequence<ManifestImageResource> icons;
+   sequence<ManifestImageResource> screenshots;
+   sequence<USVString> categories;
+   DOMString iarc_rating_id;
    USVString start_url;
    DisplayModeType display = "browser";
    OrientationLockType orientation;