Update user guide example rewrite rules formatting

Change the rewrite rule examples to include a space between the
composition of `f` and `g` in the map rewrite rule examples.

Without this change, if the user has locally enabled the extension
OverloadedRecordDot the copied example will result in a compile time
error that `g` is not a field of `f`.

```
    • Could not deduce (GHC.Records.HasField "g" (a -> b) (a1 -> b))
        arising from selecting the field ‘g’
```

1 files changed, 3 insertions, 3 deletions

diff --git a/docs/users_guide/exts/rewrite_rules.rst b/docs/users_guide/exts/rewrite_rules.rst
index 75ee2474a9..7da423f42e 100644
--- a/docs/users_guide/exts/rewrite_rules.rst
+++ b/docs/users_guide/exts/rewrite_rules.rst
@@ -16,7 +16,7 @@ The programmer can specify rewrite rules as part of the source program
 (in a pragma). Here is an example: ::
 
       {-# RULES
-            "map/map"    forall f g xs.  map f (map g xs) = map (f.g) xs
+            "map/map"    forall f g xs.  map f (map g xs) = map (f . g) xs
         #-}
 
 Use the debug flag :ghc-flag:`-ddump-simpl-stats` to see what rules fired. If
@@ -48,7 +48,7 @@ From a syntactic point of view:
    the same column as the enclosing definitions. ::
 
          {-# RULES
-               "map/map"    forall f g xs.  map f (map g xs) = map (f.g) xs
+               "map/map"    forall f g xs.  map f (map g xs) = map (f . g) xs
                "map/append" forall f xs ys. map f (xs ++ ys) = map f xs ++ map f ys
            #-}
 
@@ -63,7 +63,7 @@ From a syntactic point of view:
    :ref:`phase-control`), immediately after the name of the rule. Thus: ::
 
          {-# RULES
-               "map/map" [2]  forall f g xs. map f (map g xs) = map (f.g) xs
+               "map/map" [2]  forall f g xs. map f (map g xs) = map (f . g) xs
            #-}
 
    The ``[2]`` means that the rule is active in Phase 2 and subsequent