src/vs/editor/browser/widget/diffNavigator.ts/DiffNavigator/_move
class DiffNavigator:	private _move(fwd: boolean, scrollType: ScrollType): void {
		assert.ok(!this.disposed, 'Illegal State - diff navigator has been disposed');

		if (!this.canNavigate()) {
			return;
		}

		if (this.nextIdx === -1) {
			this._initIdx(fwd);

		} else if (fwd) {
			this.nextIdx += 1;
			if (this.nextIdx >= this.ranges.length) {
				this.nextIdx = 0;
			}
		} else {
			this.nextIdx -= 1;
			if (this.nextIdx < 0) {
				this.nextIdx = this.ranges.length - 1;
			}
		}

		const info = this.ranges[this.nextIdx];
		this.ignoreSelectionChange = true;
		try {
			const pos = info.range.getStartPosition();
			this._editor.setPosition(pos);
			this._editor.revealRangeInCenter(info.range, scrollType);
		} finally {
			this.ignoreSelectionChange = false;
		}
	}