docs: Adding the doxygen on all my function

str/ft_strnstr.c

@@ -6,12 +6,26 @@
 /*   By: rparodi <marvin@42.fr>                     +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2023/11/07 16:57:44 by rparodi           #+#    #+#             */
-/*   Updated: 2023/11/13 19:17:49 by rparodi          ###   ########.fr       */
+/*   Updated: 2024/10/31 18:12:05 by rparodi          ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
 #include "libft.h"
 
+/**
+ * @brief Locates a substring within a string, up to a specified length.
+ * 
+ * The `ft_strnstr` function locates the first occurrence of the null-terminated
+ * string `needle` within the string `haystack`,
+ * searching only up to `len` characters.
+ * 
+ * @param big The string to search.
+ * @param little The substring to locate.
+ * @param len The maximum number of characters to search.
+ * 
+ * @return A pointer to the beginning of the located substring,
+ * or NULL if `needle` is not found.
+ */
 char	*ft_strnstr(const char *big, const char *little, size_t len)
 {
 	size_t	i;