Method delete_topic

backend/src/store.rs:124–135

(
        &self,
        repo_id: RepoId,
        topic_id: &ExternalId,
    )

    }

    pub async fn delete_topic(
        &self,
        repo_id: RepoId,
        topic_id: &ExternalId,
    ) -> Result<git::DeleteTopicResult> {
        git::DeleteTopic {
            actor: Arc::clone(&self.viewer),
            repo_id,
            topic_id: topic_id.to_owned(),
        }
        .call(self.mutation()?, &self.redis)
    }

    pub async fn fetch_link(&self, link_id: ExternalId) -> Result<Option<git::Link>> {
        let key = Okey(link_id, self.viewer.context_repo_id);