fix(streaming-files): escape curly brace characters

Author: Eamonn McEvoy

content/techniques/streaming-files.md

@@ -31,7 +31,7 @@ Fastify, by default, can support sending files without needing to call `stream.p
 
 You can find a simple example of returning the `package.json` as a file instead of a JSON below, but the idea extends out naturally to images, documents, and any other file type.
 
-> info **hint** If the @Response parameter is present, it must have `{ passthrough: true }`.
+> info **hint** If the @Response parameter is present, it must have `{{ '{' }} passthrough: true {{ '}' }}`.
 
 ```ts
 import { Controller, Get, StreamableFile } from '@nestjs/common';