[numex] adding ability to handle handle the degree symbol in numex parsing since it's technically a separate token

src/numex.h

@@ -149,6 +149,7 @@ VECTOR_INIT(numex_result_array, numex_result_t)
 char *replace_numeric_expressions(char *str, char *lang);
 numex_result_array *convert_numeric_expressions(char *str, char *lang);
 size_t ordinal_suffix_len(char *s, size_t len, char *lang);
+size_t possible_ordinal_digit_len(char *str, size_t len);
 
 bool numex_table_write(FILE *file);
 bool numex_table_save(char *filename);