fix nk_window_find prototype in documentation

src/nuklear.h

@@ -1295,7 +1295,7 @@ NK_API void nk_end(struct nk_context *ctx);
 /// Finds and returns a window from passed name
 ///
 /// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~c
-/// void nk_end(struct nk_context *ctx);
+/// struct nk_window *nk_window_find(struct nk_context *ctx, const char *name);
 /// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ///
 /// Parameter   | Description