docs: adding documentation on my libft

libft/str/ft_strmapi.c

@@ -6,12 +6,21 @@
 /*   By: rparodi <marvin@42.fr>                     +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2023/11/09 13:56:57 by rparodi           #+#    #+#             */
-/*   Updated: 2023/11/13 19:49:30 by rparodi          ###   ########.fr       */
+/*   Updated: 2024/10/31 18:14:29 by rparodi          ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
 #include "libft.h"
 
+/**
+ * @brief Applies a function to each character of a string.
+ * 
+ * @param s The input string.
+ * @param f The function to apply to each character.
+ * 
+ * @return A pointer to the newly created string,
+ * or NULL if memory allocation fails.
+ */
 char	*ft_strmapi(char const *s, char (*f)(unsigned int, char))
 {
 	size_t	i;