doxygen: include mermaid state diagram in kdb.c
@@ -100,7 +100,7 @@ static void clearAllSync (KeySet * ks)
* - a conflict detection (error C02000) and
* - optimizations that avoid redoing already done operations.
*
- * @image html state.png "State"
+ * @mermaid{state}
* @image latex state.png "State"
*
* As we see in the figure, kdbOpen() can be called arbitrarily often in any
