Correct results of diff and sdiff

[antononcube]

The original implementation does not produce results that much the outputs in the documentation. This PR fixes that.

---

Old version, 0.0.2

my @a = <a b c e h j l m n p>;
my @b = <b c d e f j k l m r s t>;

my $diff = diff( @a, @b );

say $diff.raku;

gives :

$(["-", 0, "a", "+", 2, "d", "-", 4, "h", "+", 4, "f", "+", 6, "k"], ["-", 8, "n", "+", 9, "r", "-", 9, "p", "+", 10, "s", "+", 11, "t"])

---

PR's version, 0.0.3

my @a = <a b c e h j l m n p>;
my @b = <b c d e f j k l m r s t>;

my $diff = diff( @a, @b );

say $diff.raku;

gives :

$([["-", 0, "a"], ["+", 2, "d"], ["-", 4, "h"], ["+", 4, "f"], ["+", 6, "k"]], [["-", 8, "n"], ["+", 9, "r"], ["-", 9, "p"], ["+", 10, "s"], ["+", 11, "t"]])

With PR's version we get this result (in a Jupyter notebook):

[lizmat]

Thanks!