Capitalize if-then-else as other page does it

Author: jhrcek

message-index/messages/GHC-01239/example1/index.md

@@ -2,7 +2,7 @@
 title: Unexpected if expression in function application
 ---
 
-To pass if-then-else expressions as function argument we either have to surround it in parentheses,
+To pass If-Then-Else expressions as function argument we either have to surround it in parentheses,
 use function application operator `($)` or enable [`BlockArguments`](https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/block_arguments.html#extension-BlockArguments) extension.
 
 ## Error Message

message-index/messages/GHC-01239/index.md

@@ -5,15 +5,15 @@ severity: error
 introduced: TODO
 ---
 
-Unlike in many other languages, in Haskell the if-then-else construct is an expression, which means it returns a value that can be processed further.
+Unlike in many other languages, in Haskell the If-Then-Else construct is an expression, which means it returns a value that can be processed further.
 
-```language-haskell
+```haskell
 ageMessage :: Int -> String 
 ageMessage age = if age < 18 then "You are too young to enter" else "Welcome to the club"
 
 putStrLn (ageMessage 10) -- You are too young to enter
 putStrLn (ageMessage 20) -- Welcome to the club
 ```
 
-Thinking of if-then-else expression as a value, we might want to pass it as an input to a function.
+Thinking of If-Then-Else expression as a value, we might want to pass it as an input to a function.
 If you do that you can run into the following error.