Allow keyboard to activate permalink

[jonels-msft]

Fixes #956

In the new behavior, permalinks are hidden but are present for keyboard focus. When you tab into them they appear. They also appear when you mouse over the headers, as before.

The only downside is that we're falling back to using sphinx's ¶ symbol, which doesn't look as nice as fontawesome's chain link icon. However I think that's a price we have to pay for accessibility.

[Blendify]

The only downside is that we're falling back to using sphinx's ¶ symbol, which doesn't look as nice as fontawesome's chain link icon. However I think that's a price we have to pay for accessibility.

The newer sphinx version allows changing this see https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_permalinks_icon I think we should be able to change the default for this from the python side? Not sure though needs investigation...

[jonels-msft]

Is this good to merge for now?

[Blendify]

We need to see if it's possible to change the default permalink icon from python/sphinx so that there is no regression.

The change would have to be made in https://github.com/readthedocs/sphinx_rtd_theme/blob/master/sphinx_rtd_theme/__init__.py

I think this is possible using app.config.html_permalinks_icon this may be read-only though:
app.config.html_permalinks_icon = "🔗"

[jonels-msft]

@Blendify your suggestion worked perfectly in my dev environment. 😄

[Blendify]

Currently, the rendering does not match how it did previously because the font family should still be FontAwesome.

Also is there a reason behind the font size change and the adjusted margin?

[jonels-msft]

After losing the FontAwesome font family, I was adjusting the size and margin to match the original size better.

However, as you suggested, I put FontAwesome back to match the prior style even better. Did have to include a little left margin because the link icon was pressed right against the text otherwise when not in :after content.

[Blendify]

This should fix the tests from failing

    if sphinx_version >= (3, 5, 0):
        app.config.html_permalinks_icon = "🔗"
    else:
        app.config.html_add_permalinks = "🔗"

[jonels-msft]

Nice, did that. Also specified the unicode character with "\u...". Hope that kind of string literal is portable across python versions.

[jonels-msft]

@Blendify it's ready for another look.