Added tests for the Ruby kernel

[mishushakov]

• PR with tests for Added support for Ruby #106

[0div]

i'd make sure a few Ruby 3.0+ syntax changes work via additional tests such as:

• Rightward assignment: 42 => x # Assigns 42 to x
• Pattern matching: {a: 1, b: 2} => {a:} # Extracts a (= 1)
• Find pattern:

case [1, 2, 3, 4, 5]
in [*pre, 3, *post]
  [pre, post]  # => [[1, 2], [4, 5]]
end

[jakubno]

Move this to #106