Use lease_connection instead of soft deprecated connection [ci-skip]

Author: kamipo

activerecord/CHANGELOG.md

@@ -3,7 +3,7 @@
     This will let you to drop multiple tables in a single call.
 
     ```ruby
-    ActiveRecord::Base.connection.drop_table(:users, :posts)
+    ActiveRecord::Base.lease_connection.drop_table(:users, :posts)
     ```
 
     *Gabriel Sobrinho*

guides/source/active_record_postgresql.md

@@ -628,7 +628,7 @@ add_reference :alias, :person, foreign_key: { deferrable: :deferred }
 If the reference was created with the `foreign_key: true` option, the following transaction would fail when executing the first `INSERT` statement. It does not fail when the `deferrable: :deferred` option is set though.
 
 ```ruby
-ActiveRecord::Base.connection.transaction do
+ActiveRecord::Base.lease_connection.transaction do
   person = Person.create(id: SecureRandom.uuid, alias_id: SecureRandom.uuid, name: "John Doe")
   Alias.create(id: person.alias_id, person_id: person.id, name: "jaydee")
 end
@@ -637,8 +637,8 @@ end
 When the `:deferrable` option is set to `:immediate`, let the foreign keys keep the default behavior of checking the constraint immediately, but allow manually deferring the checks using `set_constraints` within a transaction. This will cause the foreign keys to be checked when the transaction is committed:
 
 ```ruby
-ActiveRecord::Base.connection.transaction do
-  ActiveRecord::Base.connection.set_constraints(:deferred)
+ActiveRecord::Base.lease_connection.transaction do
+  ActiveRecord::Base.lease_connection.set_constraints(:deferred)
   person = Person.create(alias_id: SecureRandom.uuid, name: "John Doe")
   Alias.create(id: person.alias_id, person_id: person.id, name: "jaydee")
 end

guides/source/active_record_querying.md

@@ -2307,17 +2307,17 @@ irb> Customer.find_by_sql("SELECT * FROM customers INNER JOIN orders ON customer
 
 ### `select_all`
 
-`find_by_sql` has a close relative called [`connection.select_all`][]. `select_all` will retrieve
+`find_by_sql` has a close relative called [`lease_connection.select_all`][]. `select_all` will retrieve
 objects from the database using custom SQL just like `find_by_sql` but will not instantiate them.
 This method will return an instance of `ActiveRecord::Result` class and calling `to_a` on this
 object would return you an array of hashes where each hash indicates a record.
 
 ```irb
-irb> Customer.connection.select_all("SELECT first_name, created_at FROM customers WHERE id = '1'").to_a
+irb> Customer.lease_connection.select_all("SELECT first_name, created_at FROM customers WHERE id = '1'").to_a
 => [{"first_name"=>"Rafael", "created_at"=>"2012-11-10 23:23:45.281189"}, {"first_name"=>"Eileen", "created_at"=>"2013-12-09 11:22:35.221282"}]
 ```
 
-[`connection.select_all`]: https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/DatabaseStatements.html#method-i-select_all
+[`lease_connection.select_all`]: https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/DatabaseStatements.html#method-i-select_all
 
 ### `pluck`