docs(buffer): fix possessive typo in Windows conpty comment

Change "it's view" to "its view" in the comment explaining why new
rows are appended on Windows when using conpty.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/common/buffer/Buffer.ts

@@ -197,7 +197,7 @@ export class Buffer extends Disposable implements IBuffer {
         for (let y = this._rows; y < newRows; y++) {
           if (this.lines.length < newRows + this.ybase) {
             if (this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined) {
-              // Just add the new missing rows on Windows as conpty reprints the screen with it's
+              // Just add the new missing rows on Windows as conpty reprints the screen with its
               // view of the world. Once a line enters scrollback for conpty it remains there
               this.lines.push(new BufferLine(this._stringCache, newCols, nullCell, false));
             } else {