clearified comment for function

src/date_time_handling.c

@@ -4,8 +4,8 @@
 #include <time.h>
 #include <string.h>
 
-// buffer needs to contain this string: "xxxxxxxxTxxxxxx"
-// or "YYYYmmddTHHMMSSZ"
+// buffer needs to contain a string with a strlen of 15 (format: "xxxxxxxxTxxxxxx")
+// or a strlen of 16 (format: "YYYYmmddTHHMMSSZ")
 void get_date(char buffer[]) {
 	// add 1 because strlen does not include the null character
 	size_t buffer_size = strlen(buffer) + 1;