xcm: Change TypeInfo::path to not include staging (#1948)

The `xcm` crate was renamed to `staging-xcm` to be able to publish it to
crates.io as someone as squatted `xcm`. The problem with this rename is
that the `TypeInfo` includes the crate name which ultimately lands in
the metadata. The metadata is consumed by downstream users like
`polkadot-js` or people building on top of `polkadot-js`. These people
are using the entire `path` to find the type in the type registry. Thus,
their code would break as the type path would now be [`staging_xcm`,
`VersionedXcm`] instead of [`xcm`, `VersionedXcm`]. This pull request
fixes this by renaming the path segment `staging_xcm` to `xcm`.

This requires: https://github.com/paritytech/scale-info/pull/197

---------

Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

polkadot/xcm/src/tests.rs

@@ -181,3 +181,12 @@ fn encode_decode_versioned_xcm_v3() {
 	let decoded = VersionedXcm::decode(&mut &encoded[..]).unwrap();
 	assert_eq!(xcm, decoded);
 }
+
+// With the renaming of the crate to `staging-xcm` the naming in the metadata changed as well and
+// this broke downstream users. This test ensures that the name in the metadata isn't changed.
+#[test]
+fn ensure_type_info_is_correct() {
+	let type_info = VersionedXcm::<()>::type_info();
+
+	assert_eq!(type_info.path.segments, vec!["xcm", "VersionedXcm"]);
+}