Change logout FA icon

[Info 3bits]

The existing icon is lock when it should be unlock

[Jeremy Hopkins]

It would be better to use fa-sign-out which is more consistend with core Moodle. I will raise another issue to move all this code out of header.php to a renderer, its not good the way its setup at the moment.

[Jeremy Hopkins]

Fix #367 - change logout icon to fa-sign-out making consistent with core Moodle.

→ <<cset bd68edf79865>>