Fix interface of Raw nodes to make them extendable again

Related-to:  d97bcbd.
Closes GH-65.
Closes GH-66.

Reviewed-by: Christian Murphy <[email protected]>
Reviewed-by: Titus Wormer <[email protected]>

Author: Methuselah96

complex-types.d.ts

@@ -1,17 +1,18 @@
 import type {Literal} from 'hast'
 
-export type Raw = {
+// eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+export interface Raw extends Literal {
   type: 'raw'
-} & Literal
+}
 
-/* eslint-disable @typescript-eslint/consistent-type-definitions */
 declare module 'hast' {
+  // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
   interface RootContentMap {
     raw: Raw
   }
 
+  // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
   interface ElementContentMap {
     raw: Raw
   }
 }
-/* eslint-enable @typescript-eslint/consistent-type-definitions */