Fix typos

docs/users_guide/glasgow_exts.xml

@@ -1999,8 +1999,8 @@ The rule for record update is this: <emphasis>
 the types of the updated fields may
 mention only the universally-quantified type variables
 of the data constructor.  For GADTs, the field may mention only types
-that appear as a simple type-variable argument in the constructor's result type.
-</emphasis>.  For exmaple:
+that appear as a simple type-variable argument in the constructor's result
+type</emphasis>.  For example:
 <programlisting>
 data T a where { T1 { f1::a, f2::(a,b) } :: T a }    -- b is existential
 upd1 t x = t { f1=x }   -- OK:   upd1 :: T a -> b -> T b
@@ -2010,7 +2010,7 @@ upd2 t x = t { f2=x }   -- BAD   (f2's type mentions b, which is
 data G a b where { G1 { f1::a, f2::c } :: G a [c] }
 upd3 g x = g { f1=x }   -- OK:   upd3 :: G a b -> c -> G c b
 upd4 g x = g { f2=x }   -- BAD (f2's type mentions c, which is not a simple
-                        --      type-varialbe argument in G1's result type)
+                        --      type-variable argument in G1's result type)
 </programlisting>
 </para>