docs: Improve example code formatting

Improve code formatting to adhere to Clutter uncrustify rules.

doc/cookbook/examples/cb-button.c

@@ -20,15 +20,13 @@ struct _CbButtonPrivate
 };
 
 /* enumerates signal identifiers for this class */
-enum
-{
+enum {
   CLICKED,
   LAST_SIGNAL
 };
 
 /* enumerates property identifiers for this class */
-enum
-{
+enum {
   PROP_0,
   PROP_TEXT
 };

doc/cookbook/examples/cb-button.h

@@ -23,7 +23,7 @@ GType cb_button_get_type (void);
 
 /*
  * Private instance fields; see
- * http://www.gotw.ca/gotw/024.htm for the rationalse
+ * http://www.gotw.ca/gotw/024.htm for the rationale
  */
 typedef struct _CbButtonPrivate CbButtonPrivate;
 typedef struct _CbButton        CbButton;
@@ -44,7 +44,7 @@ struct _CbButton
 struct _CbButtonClass
 {
   /* signals */
-  void (* clicked) (CbButton *button);
+  void (* clicked)(CbButton *button);
 
   /*<private>*/
   ClutterActorClass parent_class;
@@ -61,7 +61,8 @@ G_CONST_RETURN gchar * cb_button_get_text (CbButton *self);
 /* setters - these are wrappers round functions
  * which change properties of the internal actors
  */
-void cb_button_set_text (CbButton *self, const gchar *text);
+void cb_button_set_text (CbButton    *self,
+                         const gchar *text);
 
 void cb_button_set_background_color (CbButton           *self,
                                      const ClutterColor *color);