Codechange: Using alias and std::array for company expense storage. (#11273)

This simplifies passing yearly expenses to functions and use of std algorithms.

src/economy_type.h

@@ -172,6 +172,11 @@ enum ExpensesType : byte {
 	INVALID_EXPENSES      = 0xFF, ///< Invalid expense type.
 };
 
+/**
+ * Data type for storage of Money for each #ExpensesType category.
+ */
+using Expenses = std::array<Money, EXPENSES_END>;
+
 /**
  * Categories of a price bases.
  */