[vinyl][vinyl-file] Fix 5.5 nightly errors (DefinitelyTyped#69319)

types/vinyl-file/index.d.ts

@@ -15,21 +15,6 @@ export interface VinylFileOptions {
     read?: boolean | undefined;
 }
 export interface VinylFile extends File {
-    /** Returns true if the file contents are a Buffer, otherwise false */
-    isStream: () => boolean;
-
-    /** Returns true if the file contents are a Stream, otherwise false */
-    isBuffer: () => boolean;
-
-    /** Returns true if the file contents are null, otherwise false */
-    isNull: () => boolean;
-
-    /** Returns true if the file represents a directory, otherwise false */
-    isDirectory: () => boolean;
-
-    /** Returns true if the file represents a symbolic link, otherwise false */
-    isSymbolic: () => boolean;
-
     /** Returns a new Vinyl object with all attributes cloned. */
     clone(opts?: { contents?: boolean | undefined; deep?: boolean | undefined } | boolean): this;
 

types/vinyl/index.d.ts

@@ -335,15 +335,13 @@ declare namespace File {
     interface BufferFile extends File {
         contents: Buffer;
         isStream(): this is never;
-        isBuffer(): true;
         isNull(): this is never;
         isDirectory(): this is never;
         isSymbolic(): this is never;
     }
 
     interface StreamFile extends File {
         contents: NodeJS.ReadableStream;
-        isStream(): true;
         isBuffer(): this is never;
         isNull(): this is never;
         isDirectory(): this is never;
@@ -354,18 +352,15 @@ declare namespace File {
         contents: null;
         isStream(): this is never;
         isBuffer(): this is never;
-        isNull(): true;
         isDirectory(): this is DirectoryFile;
         isSymbolic(): this is SymbolicFile;
     }
 
     interface DirectoryFile extends NullFile {
-        isDirectory(): true;
         isSymbolic(): this is never;
     }
 
     interface SymbolicFile extends NullFile {
         isDirectory(): this is never;
-        isSymbolic(): true;
     }
 }