Fixed incorrect types in nodegit class DiffDelta and Blob (#41314)

* Fixes incorrect return types in diff-delta and blob. Should be functions, not direct accessor properties. Also, `rawcontent` returns a wrapper around a Buffer, not a Buffer directly, as `content` does.

* updated package description and version

* fixed missing argument

* Updates jackrabbit types to export namespace for interface and type access. Adds missing options and arguments to a few methods.

* fixed linting issue

* revert changes to jackrabbit

types/nodegit/blob.d.ts

@@ -1,5 +1,5 @@
 import { WriteStream } from 'fs';
-
+import { Wrapper } from "./wrapper";
 import { Repository } from './repository';
 import { Oid } from './oid';
 
@@ -31,7 +31,7 @@ export class Blob {
     id(): Oid;
     isBinary(): number;
     owner(): Repository;
-    rawcontent(): Buffer;
+    rawcontent(): Wrapper;
     rawsize(): number;
     content(): Buffer;
     toString(): string;

types/nodegit/diff-delta.d.ts

@@ -1,10 +1,10 @@
 import { DiffFile } from './diff-file';
 
 export class DiffDelta {
-    status: number;
-    flags: number;
-    similarity: number;
-    nfiles: number;
-    oldFile: DiffFile;
-    newFile: DiffFile;
+    status: () => number;
+    flags: () => number;
+    similarity: () => number;
+    nfiles: () => number;
+    oldFile: () => DiffFile;
+    newFile: () => DiffFile;
 }

types/nodegit/index.d.ts

@@ -1,9 +1,10 @@
-// Type definitions for nodegit 0.24
+// Type definitions for nodegit 0.26
 // Project: https://github.com/nodegit/nodegit, http://nodegit.org
 // Definitions by: Dolan Miu <https://github.com/dolanmiu>,
 //                 Tobias Nießen <https://github.com/tniessen>,
 //                 Pierre Vigier <https://github.com/pvigier>
 //                 Jibril Saffi <https://github.com/IGI-111>
+//                 Benjamin Schuster-Boeckler <https://github.com/DaGaMs>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 export { AnnotatedCommit } from './annotated-commit';

types/nodegit/wrapper.d.ts

@@ -0,0 +1,3 @@
+export class Wrapper {
+    toBuffer(bufSize: number): Buffer;
+}