Allow tuple basename for Tempfile.{new,create} methods

[ybiquitous]

This change allows the basename parameter receives a 2-strings tuple for the Tempfile.new and Tempfile.create methods.

The Tempfile.new doc says:

The basename parameter is used to determine the name of the temporary file.
You can either pass a String or an Array with 2 String elements. In the former
form, the temporary file's base name will begin with the given string. In the
latter form, the temporary file's base name will begin with the array's first
element, and end with the second element. For example:

[pocke]

LGTM 🌟

[pocke]

By the way, I've confirmed the tmpdir signature doesn't have the same problem ✔️

rbs/stdlib/tmpdir/0/tmpdir.rbs

Lines 51 to 52 in a402b00

	def self.mktmpdir: (?(String | [ String, String ] | nil), ?String?, ?max_try: Integer?) -> String
	| [X] (?(String | [ String, String ] | nil), ?String?, ?max_try: Integer?) { (String) -> X } -> X

[ybiquitous]

@pocke Thanks for the review and merge! 😄