Raku syntax: Fix strings and comments (#2311)

Raku syntax: Fix strings and comments (#2311)

* Raku syntax: Fix strings and comments

Problematic code:
my @array1 = [
   "'", "a", "b"
];
my @array2 = [
   '"', 'a', 'b'
];
my @array3 = [
   "#", "a", "b"
];

I deleted "default" because it was breaking comments with urls after
of my changes.

Some parts were taken from:
https://github.com/hankache/raku.nanorc/blob/master/raku.nanorc

* Raku syntax: fix strings

Code:
sub xyz(Str is encoded('utf8')) returns int32 is native('asdf') { * }
sub xyz(Str is encoded("utf8")) returns int32 is native("asdf") { * }

From python3.yaml