extensions/git/src/model.ts/Model/registerPostCommitCommandsProvider
class Model:	registerPostCommitCommandsProvider(provider: PostCommitCommandsProvider): Disposable {
		this.postCommitCommandsProviders.add(provider);
		this._onDidChangePostCommitCommandsProviders.fire();

		return toDisposable(() => {
			this.postCommitCommandsProviders.delete(provider);
			this._onDidChangePostCommitCommandsProviders.fire();
		});
	}