Fix docs application of generics to nested interfaces (#4104)

Co-authored-by: Danni <[email protected]>

Author: snowystinger

packages/dev/parcel-packager-docs/DocsPackager.js

@@ -102,6 +102,8 @@ module.exports = new Packager({
             params[p.name] = v;
           });
           paramStack.push(params);
+          // so we don't replace the type parameters in the extended interface
+          application = null;
           hasParams = true;
         } else if (t && (t.type === 'alias' || t.type === 'interface' || t.type === 'component') && t.typeParameters && keyStack.length === 0) {
           // If we are at a root export, replace type parameters with constraints if possible.