docs: move keysym-transformations page to a better position

Signed-off-by: Ran Benita <ran234@gmail.com>

xkbcommon/xkbcommon.h

@@ -362,6 +362,13 @@ struct xkb_rule_names {
     const char *options;
 };
 
+/**
+ * @defgroup keysyms Keysyms
+ * Utility functions related to keysyms.
+ *
+ * @{
+ */
+
 /**
  * @page keysym-transformations Keysym Transformations
  *
@@ -390,12 +397,6 @@ struct xkb_rule_names {
  * keysyms.
  */
 
-/**
- * @defgroup keysyms Keysyms
- * Utility functions related to keysyms.
- *
- * @{
- */
 
 /**
  * Get the name of a keysym.