[utf8] Adding method to get the script of a string and the length of the span (rolls Common script up with the previuos script)

src/unicode_scripts.h

@@ -2,6 +2,7 @@
 #define UNICODE_SCRIPTS_H
 
 #include <stdlib.h>
+#include "utf8proc/utf8proc.h"
 #include "unicode_script_types.h"
 
 typedef struct script_code {
@@ -17,4 +18,6 @@ typedef struct script_languages {
 script_t get_char_script(uint32_t ch);
 script_languages_t get_script_languages(script_t script);
 
+script_t string_script(char *str, size_t *len);
+
 #endif