[accessibility] Keyboard and screen reader support for `leaflet-control-dialog-close`

[Malvoz]

• The control is not focusable, it should be a <button type="button"> or role="button" (with tabindex="0" or <a href="#">).
• aria-label or title can be used to allow screen reader users to understand what the control is for.
  For example title="Close dialog".

[Malvoz]

Other resources that you may find helpful:

• Leaflet guide to accessibility: Test your maps
• Leaflet Plugin Authoring Guide: Content Accessibility

[valerio-bozzolan]

Hi Malboz,

At the moment the maintainer of this project is not available. But here there is a more updated fork:

https://github.com/canterbury-air-patrol/Leaflet.Dialog