Raku name changes for LEARNING doc (#355)
Raku name changes for LEARNING doc (#355)

- Remove broken link
- update domain names for documentation to new Raku name.
mienaikage/exercism-perl6,mienaikage/exercism-perl6,mienaikage/xperl6,mienaikage/exercism-perl6,mienaikage/xperl6,mienaikage/xperl6,exercism/xperl6,exercism/xperl6,exercism/xperl6