ESLint: Enable @typescript-eslint/return-await rule

This ensures stack traces are helpful at the cost of a slightly
lower performance (one more tick in the event loop).

Fixes #838

Signed-off-by: David Mehren <git@herrmehren.de>

src/history/history.service.ts

@@ -79,7 +79,7 @@ export class HistoryService {
       );
     }
     entry.pinStatus = updateDto.pinStatus;
-    return this.historyEntryRepository.save(entry);
+    return await this.historyEntryRepository.save(entry);
   }
 
   async deleteHistoryEntry(noteIdOrAlias: string, user: User): Promise<void> {