Text elements must have sufficient colour contrast against the background,
restyling the link element when it is focused is to ensure colour contrast of at least 4.5:1
Bootstrap core's "reboot" sets a default text-align which is
incompatible with RTL languages.
Arguably this should be set in the Boost theme, but this is a fairly
large change which has potential to break things so I'm making it here
where we experience the issue for now.
Part of MDL-75966
This commit adds TinyMCE version 6.1 into Moodle core.
A basic editor implementation is included, along with Moodle loader, and
basic Plugin API for Moodle. The Plugin API will be extended and
improved in future changes.
A new subplugin is defined for this plugin.