feat: added more lst functionality

srcs/lst/ft_lstfind.c

@@ -0,0 +1,12 @@
+#include "libft.h"
+
+t_list *ft_lstfind(t_list *lst, void *data, int (*cmp)(void *, void *))
+{
+    while (lst)
+    {
+        if (cmp(lst->data, data) == 0)
+            return (lst);
+        lst = lst->next;
+    }
+    return (NULL);
+}