doc: change exception handler lambda to take two parameters

doc/sample/Person.im

@@ -304,9 +304,9 @@ a = (32, 64).
 try
     v = Int parse:'342'
 catch (#err:number_format, err) in
-    cout put:'Cannot parse integer string ({err msg})'
+    cout put:'Cannot parse integer string ({err})'
 catch (_, err) in
-    cout put:'Unknown error occurred ({err msg})'
+    cout put:'Unknown error occurred ({err})'
 end
 
 /* equivalent 'pure' syntax */
@@ -335,11 +335,11 @@ end
  **/
 
 [ v = Int parse:'342' ]
-    on:#err:number_format do:[ :err |
-        cout put:'Cannot parse integer string ({err msg})'
+    on:#err:number_format do:[ :err :data |
+        cout put:'Cannot parse integer string ({err})'
     ];
-    onError:[ :err |
-        cout put:'Unknown error occurred ({err msg})'
+    onError:[ :err :data |
+        cout put:'Error {err} occurred ({data})'
     ];
     call.