activerecord: Add types for load_async (#767)

This method has been added since 7.0

- rails/rails#41372
- https://github.com/rails/rails/blob/7-0-stable/activerecord/CHANGELOG.md

gems/activerecord/7.0/_test/test.rb

@@ -26,6 +26,7 @@ class Article < ActiveRecord::Base
   end
 
   User.where.missing.to_sql
+  User.where(role: :admin).load_async
   User.deterministic_encrypted_attributes
   User.source_attribute_from_preserved_attribute(:phrase)
   User.insert({ id: 1, name: 'James' }, returning: %i[id name], unique_by: :id, record_timestamps: true)

gems/activerecord/7.0/activerecord-7.0.rbs

@@ -8,6 +8,10 @@ module ActiveRecord
     end
   end
 
+  class Relation
+    def load_async: () -> Relation
+  end
+
   module Core
     def values_at: (*Symbol | String) -> Array[untyped]
     def strict_loading!: (?bool value, ?mode: Symbol) -> bool

gems/activerecord/7.1/_test/test.rb

@@ -33,6 +33,7 @@ class Article < ActiveRecord::Base
   end
 
   User.where.missing.to_sql
+  User.where(role: :admin).load_async
   User.deterministic_encrypted_attributes
   User.source_attribute_from_preserved_attribute(:phrase)
   User.insert({ id: 1, name: 'James' }, returning: %i[id name], unique_by: :id, record_timestamps: true)

gems/activerecord/7.1/activerecord-7.1.rbs

@@ -176,6 +176,8 @@ end
 
 module ActiveRecord
   class Relation
+    def load_async: () -> Relation
+
     module Methods[Model, PrimaryKey]
       def authenticate_by: (untyped attributes) -> Model?
     end

gems/activerecord/7.2/_test/test.rb

@@ -31,6 +31,7 @@ class Article < ApplicationRecord
   end
 
   User.where.missing.to_sql
+  User.where(role: :admin).load_async
   User.deterministic_encrypted_attributes
   User.source_attribute_from_preserved_attribute(:phrase)
   User.insert({ id: 1, name: 'James' }, returning: %i[id name], unique_by: :id, record_timestamps: true)

gems/activerecord/7.2/activerecord-7.2.rbs

@@ -29,6 +29,7 @@ module ActiveRecord
     def insert_all!: (untyped attributes, ?returning: untyped?, ?record_timestamps: bool?) -> untyped
     def upsert: (untyped attributes, ?unique_by: untyped?, ?returning: untyped?, ?record_timestamps: bool?) -> untyped
     def upsert_all: (untyped attributes, ?unique_by: untyped?, ?returning: untyped?, ?record_timestamps: bool?) -> untyped
+    def load_async: () -> Relation
   end
 
   module Inheritance