Delete element from array by value

---

examples/arrays/delete.cr

planets = ["Mercury", "Venus", "Earth", "Mars", "Jupiter"]
puts planets.delete("Earth")
puts planets

res = planets.delete("Pluto")
puts res.nil?
puts planets

names = ["Foo", "Bar", "Foo"]
names.delete("Foo")
puts names

Earth
["Mercury", "Venus", "Mars", "Jupiter"]
true
["Mercury", "Venus", "Mars", "Jupiter"]
["Bar"]