Test resulting mime against those in supported.js ?

[sly7-7]

Description

It seems to me it could improve the test harness by checking if the result of the functions is consistent with the one in supported.js.
for example here:

file-type/test.js

Line 307 in 7e72bbc

t.is(typeof mime, 'string');

using something like t.true(supportedMimeTypes.has(mime));

Existing Issue Check

• I have searched the existing issues and could not find any related to my problem.

File-Type Scope Acknowledgment

• I understand that file-type detects binary file types and not text or other formats.