fix(guide): simplify directory structure

guide/english/haskell/hello-world/index.md

@@ -0,0 +1,24 @@
+---
+title: Hello World Program
+---
+
+## The simplest Hello World Program in Haskell
+```haskell
+main :: IO ()
+main = do
+    putStrLn "Hello World"
+```
+
+## Hello World using function composition
+
+```haskell
+hello :: String
+hello = "Hello World"
+
+printer :: String -> IO ()
+printer = putStrLn . show 
+
+main :: IO ()
+main = printer hello
+
+```