Added a page for list comprehensions in haskell (#30741)

guide/english/haskell/list-comprehension/index.md

@@ -0,0 +1,21 @@
+---
+title: List Comprehensions
+---
+
+## List Comprehensions
+
+List comprehensions are a powerful tool in haskell for working with sets.
+
+```haskell
+someNumbers :: [Int] # a list of integers containing, 1, 2 and 3
+someNumbers = [1,2,3] 
+
+allLower  :: [Char] 
+allLower = [toLower c | c <- "Hello, World!" ]
+
+parity :: [(Int, Boolean)]
+parity = [ ( x , even x ) | x <- [1,2,3] ]
+```
+Parity produces the following set: `[ (1, False), (2, True), (3, False) ]`
+
+The right hand side of the list comprehension is composed of two parts; a generator and guards.