trizen/raku-rosettacode: Tasks from Rosettacode implemented in Raku @ 22.07

trizen 986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.		%!s(int64=4) %!d(string=hai) anos
..
Arithmetic_mean.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Mean_angle.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Mean_time_of_day.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Median.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Mode.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Pythagorean_means.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Root_mean_square.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos
Simple_moving_average.md	986b637005 Gitbook does not yet understand the `raku` language tag. Revert to `perl`.	%!s(int64=4) %!d(string=hai) anos