Module is inaccessible

Problem/Motivation

Module is inaccessible in current form:

• Eye element is a span, rather than a button which is the proper element for performing actions on a page like toggling elements. As a span, it is not focusable, meaning it is unreachable and unusable for users who navigate with the keyboard
• Eye element has no associated text, meaning it is totally undiscoverable and unusable for screen reader users

Steps to reproduce

Install module

Proposed resolution

Convert span to button element and add visually hidden text to indicate button purpose

Remaining tasks

Test and incorporate attached patch (or propose improvements)

Hidden button text is translateable through Drupal interface; just clear caches after patching.