Fix doxygen

Use `\return` not `\returns`

Author: alinaliBQ

cpp/src/arrow/flight/sql/odbc/odbc_api.cc

@@ -830,7 +830,7 @@ SQLRETURN SQLFetch(SQLHSTMT stmt) {
     ODBCStatement* statement = reinterpret_cast<ODBCStatement*>(stmt);
 
     // The SQL_ATTR_ROW_ARRAY_SIZE statement attribute specifies the number of rows in the
-    // rowset.
+    // rowset. Retrieve it with GetArraySize.
     ODBCDescriptor* ard = statement->GetARD();
     size_t rows = static_cast<size_t>(ard->GetArraySize());
 

cpp/src/arrow/flight/sql/odbc/odbc_impl/spi/result_set.h

@@ -89,7 +89,7 @@ class ResultSet {
   /// \param buffer Target buffer to be populated.
   /// \param buffer_length Target buffer length.
   /// \param strlen_buffer Buffer that holds the length of value being fetched.
-  /// \returns SQLRETURN for SQLGetData.
+  /// \return SQLRETURN for SQLGetData.
   virtual SQLRETURN GetData(int column, int16_t target_type, int precision, int scale,
                             void* buffer, size_t buffer_length,
                             ssize_t* strlen_buffer) = 0;