Fix typos and trailing whitespace

src/ShellCheck/Checks/Custom.hs

@@ -1,7 +1,7 @@
 {-
     This empty file is provided for ease of patching in site specific checks.
     However, there are no guarantees regarding compatibility between versions.
--} 
+-}
 
 {-# LANGUAGE TemplateHaskell #-}
 module ShellCheck.Checks.Custom (checker, ShellCheck.Checks.Custom.runTests) where