diesel: Do not automatically generate schema

It currently can’t handle views, so it has to be updated manually based
on diesel print-schema.

diesel.toml

@@ -6,7 +6,6 @@
 # see https://diesel.rs/guides/configuring-diesel-cli
 
 [print_schema]
-file = "src/schema.rs"
 custom_type_derives = ["diesel::query_builder::QueryId"]
 
 [migrations_directory]

src/schema.rs

@@ -2,8 +2,6 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-// @generated automatically by Diesel CLI.
-
 diesel::table! {
     items (id) {
         id -> Uuid,