Merge pull request #74 from haskell-servant/wip-whitespace-comment

servant: clean up some white spaces, add link explaining why Or works.

servant/src/Servant/Utils/Links.hs

@@ -138,6 +138,8 @@ data Link = Link
 
 -- | If either a or b produce an empty constraint, produce an empty constraint.
 type family Or (a :: Constraint) (b :: Constraint) :: Constraint where
+    -- This works because of:
+    -- https://ghc.haskell.org/trac/ghc/wiki/NewAxioms/CoincidentOverlap
     Or () b       = ()
     Or a ()       = ()
 
@@ -145,8 +147,8 @@ type family Or (a :: Constraint) (b :: Constraint) :: Constraint where
 type family And (a :: Constraint) (b :: Constraint) :: Constraint where
     And () ()     = ()
 
--- | You may use this type family to tell the type checker that your custom type
--- may be skipped as part of a link. This is useful for things like
+-- | You may use this type family to tell the type checker that your custom
+-- type may be skipped as part of a link. This is useful for things like
 -- 'QueryParam' that are optional in a URI and do not affect them if they are
 -- omitted.
 --