Update core.d.ts

Simplify file type detector description

Co-authored-by: Sindre Sorhus <[email protected]>

Author: Borewit

core.d.ts

@@ -114,7 +114,7 @@ console.log(await fileTypeFromBlob(blob));
 export declare function fileTypeFromBlob(blob: Blob): Promise<FileTypeResult | undefined>;
 
 /**
-A custom detector is a function that allows specifying custom detection mechanisms.
+A custom file type detector.
 
 An array of detectors can be provided via the `fileTypeOptions` argument for the `FileTypeParser` constructor.
 In Node.js, you should use `NodeFileTypeParser`, which extends `FileTypeParser` and provides access to Node.js specific functions.