Feature: `file_t` constructor now allows non-allocatable `string_t` array actual arguments

This release facilitates passing expressions and other non-allocatable actual arguments to the file_t constructor function that takes a string_t array dummy argument containing the a file's lines.

What's Changed

• Feature: file_t constructor now allows non-allocatable string_t array actual arguments by @rouson in #62

Full Changelog: 4.4.2...4.4.3