Use IOMSG for errors

[jacobwilliams]

I/O operations can also return a iomsg string variable for errors (e.g., for open or write). Probably should use that and add those messages to any error reporting that is done (prints or exception messages).

Reference

• https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2023-0/i-o-message-specifier-iomsg.html