git: add 'signed off' commit to git changes view

This adds 2 actions to the context menu in the git changes view: 'Commit Staged (Signed Off)' and 'Commit All (Signed Off)'.

src/vs/workbench/parts/git/browser/views/changes/changesView.ts

@@ -282,7 +282,9 @@ export class ChangesView extends EventEmitter.EventEmitter implements GitView.IV
 				this.instantiationService.createInstance(GitActions.PublishAction, GitActions.PublishAction.ID, GitActions.PublishAction.LABEL),
 				new ActionBar.Separator(),
 				this.instantiationService.createInstance(GitActions.CommitAction, this),
+				this.instantiationService.createInstance(GitActions.CommitSignedOffAction, this),
 				this.instantiationService.createInstance(GitActions.StageAndCommitAction, this),
+				this.instantiationService.createInstance(GitActions.StageAndCommitSignedOffAction, this),
 				this.instantiationService.createInstance(GitActions.UndoLastCommitAction, GitActions.UndoLastCommitAction.ID, GitActions.UndoLastCommitAction.LABEL),
 				new ActionBar.Separator(),
 				this.instantiationService.createInstance(GitActions.GlobalUnstageAction),