Improve batch types

[DmitryScaletta]

It's currently impossible to pass dynamic arrays to db.batch function.
But sometimes it can be useful.

Before

const batchResponse0 = await db.batch(
  ['foo', 'bar'].map((channel) =>
    db.query.messages.findMany({
      where: eq(messages.channel, channel),
      limit: 100,
    }),
  ),
);
/*
Error: Argument of type 
'SQLiteRelationalQuery<"async", {
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
}[]>[]'
is not assignable to parameter of type 
'readonly [BatchItem<"sqlite">, ...BatchItem<"sqlite">[]]'.
Source provides no match for required element at position 0 in target.
*/

After

import { eq } from 'drizzle-orm';
import { drizzle } from 'drizzle-orm/libsql';
import { text, integer, sqliteTable } from 'drizzle-orm/sqlite-core';
import { createClient } from '@libsql/client';

export const messages = sqliteTable('message', {
  id: integer('id').primaryKey(),
  channel: text('channel').notNull(),
  message: text('message', { length: 512 }).notNull(),
  timestamp: integer('timestamp', { mode: 'timestamp' }).notNull(),
});

const client = createClient({ url: '', authToken: '' });
const db = drizzle(client, { schema: { messages } });

const batchResponse0 = await db.batch(
  ['foo', 'bar'].map((channel) =>
    db.query.messages.findMany({
      where: eq(messages.channel, channel),
      limit: 100,
    }),
  ),
);
/*
const batchResponse0: {
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
}[][]
*/

// tuples still work
const batchResponse1 = await db.batch([
  db.query.messages.findMany({}),
  db.query.messages.findFirst(),
]);
/*
const batchResponse1: [{
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
}[], {
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
} | undefined]
*/

const arr2: ReturnType<typeof db.query.messages.findFirst>[] = [];
const batchResponse2 = await db.batch(arr2);
/*
const batchResponse2: ({
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
} | undefined)[]
*/

const batchResponse3 = await db.batch(
  [1, 2].map((id) =>
    db.query.messages.findFirst({ where: eq(messages.id, id) }),
  ),
);
/*
const batchResponse3: ({
  id: number;
  timestamp: Date;
  channel: string;
  message: string;
} | undefined)[]
*/

const arr4 = [];
arr4.push(db.query.messages.findFirst());
arr4.push(db.query.messages.findMany());
const batchResponse4 = await db.batch(arr4);
/*
const batchResponse4: ({
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
} | {
  id: number;
  channel: string;
  message: string;
  timestamp: Date;
}[] | undefined)[]
*/

I couldn't run tests but they should work.