Literal Array #sort_by! (#272)

Closes #205.

Plus changes the title of the `#sort` test and adds one for `#sort!`.

lib/literal/array.rb

@@ -539,6 +539,11 @@ def sort!(...)
 		self
 	end
 
+	def sort_by!(...)
+		@__value__.sort_by!(...)
+		self
+	end
+
 	def take(...)
 		__with__(@__value__.take(...))
 	end

test/array.test.rb

@@ -250,7 +250,7 @@
 	assert_equal (array <=> other), -1
 end
 
-test "#sort sorts the array" do
+test "#sort returns a new sorted array" do
 	array = Literal::Array(Integer).new(3, 2, 1)
 
 	result = array.sort
@@ -259,6 +259,20 @@
 	assert_equal result.to_a, [1, 2, 3]
 end
 
+test "#sort! sorts the array in place" do
+	array = Literal::Array(Integer).new(3, 2, 1)
+	array.sort!
+
+	assert_equal array.to_a, [1, 2, 3]
+end
+
+test "#sort_by! sorts the array given a block" do
+	array = Literal::Array(String).new("Lucy", "Stephen", "Bob")
+	array.sort_by!(&:size)
+
+	assert_equal array.to_a, ["Bob", "Lucy", "Stephen"]
+end
+
 test "#push appends single value" do
 	array = Literal::Array(Integer).new(1, 2, 3)