message: feat(techdocs-node): accept sequence node custom tags
  This change to the MKDOCS_SCHEMA lets the validation logic accept
  custom tags that are sequence nodes as valid.
diff: @@ -134,6 +134,14 @@ export const MKDOCS_SCHEMA = DEFAULT_SCHEMA.extend([
  instanceOf: UnknownTag,
  construct: (data: string, type?: string) => new UnknownTag(data, type),
  }),
  + new Type('', {
  + kind: 'sequence',
  + multi: true,
  + representName: o => (o as UnknownTag).type,
  + represent: o => (o as UnknownTag).data ?? '',
  + instanceOf: UnknownTag,
  + construct: (data: string, type?: string) => new UnknownTag(data, type),
  + }),
  ]);
  /**
  