Table of contents can expand -- but not collapse -- via keyboard controls

[jonels-msft]

Problem

Those who need to use the keyboard to navigate the side menu are not able to collapse opened menu items. This may impact their efficiency.

Reproducible Project

https://pg-auto-failover.readthedocs.io/en/latest/

Error Logs/Results

Here is a video demonstrating the problem: https://www.youtube.com/watch?v=ZV_xl6PL6ag&feature=youtu.be

Expected Results

For accessibility, the menu should be compliant with WCAG 2.1.1

Pressing enter with an open menu item selected should close it again.

Environment Info

• Python Version: 3.7.3
• Sphinx Version: 1.8.5
• RTD Theme Version: 0.4.3