docs(backend): 📝 add info on csp choices

src/csp/middleware.ts

@@ -6,6 +6,8 @@ export function useCsp(
     response: Response,
     ctx: FreshContext,
 ) {
+	//See https://developer.mozilla.org/en-US/docs/Web/Security/Practical_implementation_guides/CSP
+    
     const trustedDomains = ["'self'", 'https://git.cohabit.fr']
 
     const cspRules: CspRules = {