Improve some descriptions a little bit

lib/koans/04_tuples.ex

@@ -1,35 +1,35 @@
 defmodule Tuples do
   use Koans
 
-  koan "tuples have a size" do
+  koan "Tuples have a size" do
     assert tuple_size({:a, :b, :c}) == :__
   end
 
-  koan "tuples can contain different things" do
+  koan "Tuples can contain different things" do
     assert {:a, 1, "hi"} == :__
   end
 
-  koan "you can pull out individual elements" do
+  koan "You can pull out individual elements" do
     assert elem({:a, "hi"}, 1) == :__
   end
 
-  koan "you can change individual elements of a tuple" do
+  koan "You can change individual elements of a tuple" do
     assert put_elem({:a, "hi"}, 1, "bye") == :__
   end
 
-  koan "you can also simply extend a tuple with new stuff" do
+  koan "You can also simply extend a tuple with new stuff" do
     assert Tuple.insert_at({:a, "hi"}, 1, :new_thing) == :__
   end
 
-  koan "add things at the end" do
+  koan "Add things at the end" do
     assert Tuple.append({"Huey", "Dewey"}, "Louie") == :__
   end
 
-  koan "or also remove them" do
+  koan "Or remove them" do
     assert Tuple.delete_at({:this, :is, :not, :awesome}, 2) == :__
   end
 
-  koan "turn it into a list in case you need it" do
+  koan "Turn it into a list in case you need it" do
     assert Tuple.to_list({:this, :can, :be, :a, :list}) == :__
   end
 end

lib/koans/05_lists.ex

@@ -9,10 +9,6 @@ defmodule Lists do
     assert List.last([1, 2, 3]) == :__
   end
 
-  koan "Diversity is embraced" do
-    assert [1, 2] ++ [:a, "b"] == :__
-  end
-
   koan "Things can evolve" do
     assert [1, 2, 3] -- [3] == :__
   end

lib/koans/06_maps.ex

@@ -17,15 +17,15 @@ defmodule Maps do
     assert Map.values(%{ :name => "Jon", :last_name => "Snow", :age => 27 }) == :__
   end
 
-  koan "Fetching a value returns a touple with ok when it exists..." do
+  koan "Fetching a value returns a tuple with ok when it exists" do
     assert Map.fetch(%{ :name => "Jon", :last_name => "Snow", :age => 27 }, :age) == :__
   end
 
-  koan "...or the atom :error when it doesnt." do
+  koan "Or the atom :error when it doesnt" do
     assert Map.fetch(%{ :name => "Jon", :last_name => "Snow", :age => 27 }, :family) == :__
   end
 
-  koan "Extending a map is a simple as put'ing in a new pair" do
+  koan "Extending a map is a simple as putting in a new pair" do
     assert Map.put(%{ :name => "Jon", :last_name => "Snow"}, :age, 27) == :__
   end
 
@@ -33,7 +33,7 @@ defmodule Maps do
     assert Map.put(%{ :name => "Jon", :last_name => "Snow", :age => 15}, :age, 27) == :__
   end
 
-  koan "Or you can use some syntactic sugar for exiting elements." do
+  koan "Or you can use some syntactic sugar for exiting elements" do
     initial = %{ :name => "Jon", :last_name => "Snow", :age => 16}
     assert %{ initial | :age => 27 } == :__
   end
@@ -46,7 +46,7 @@ defmodule Maps do
     assert Map.new( [{:name, "Jon"}, {:last_name, "Snow"}, {:age, 27}] ) == :__
   end
 
-  koan "Going back to a list of pairs is just as easy." do
+  koan "Going back to a list of pairs is just as easy" do
     assert Map.to_list(%{ :name => "Jon", :last_name => "Snow", :age => 27 }) == :__
   end