refactor: Refactored code in functions of query_methods.

This is done because concerns of respective steps can be separated,
which in turns leads to easier walkthrough and verbosity. Also
stretching a function to large horizontal bounds doesn't looks good.

activerecord/lib/active_record/relation/query_methods.rb

@@ -1334,21 +1334,15 @@ def validate_order_args(args)
       end
 
       def preprocess_order_args(order_args)
-        order_args.reject!(&:blank?)
-        order_args.map! do |arg|
-          klass.sanitize_sql_for_order(arg)
-        end
-        order_args.flatten!
-
+        order_args = sanitize_order_arguments(order_args)
         @klass.disallow_raw_sql!(
           order_args.flat_map { |a| a.is_a?(Hash) ? a.keys : a },
           permit: connection.column_name_with_order_matcher
         )
 
         validate_order_args(order_args)
 
-        references = order_args.grep(String)
-        references.map! { |arg| arg =~ /^\W?(\w+)\W?\./ && $1 }.compact!
+        references = column_references(order_args)
         references!(references) if references.any?
 
         # if a symbol is given we prepend the quoted table name
@@ -1371,6 +1365,21 @@ def preprocess_order_args(order_args)
         end.flatten!
       end
 
+      def sanitize_order_arguments(order_args)
+        order_args.reject!(&:blank?)
+        order_args.map! do |arg|
+          klass.sanitize_sql_for_order(arg)
+        end
+        order_args.flatten!
+        order_args
+      end
+
+      def column_references(order_args)
+        references = order_args.grep(String)
+        references.map! { |arg| arg =~ /^\W?(\w+)\W?\./ && $1 }.compact!
+        references
+      end
+
       def order_column(field)
         arel_column(field) do |attr_name|
           if attr_name == "count" && !group_values.empty?