Function get_idx_after_strict 

pub fn get_idx_after_strict<'a>(text: &'a str, end: &str) -> Option<usize>

Return the index of the end of an occurence. Return None if there is no occurence.

use string_tools::get_idx_after_strict;
 
assert_eq!(get_idx_after_strict("azertyuiopqsdfghjklmwxcvbn", "sdf"), Some(14));
assert_eq!(get_idx_after_strict("azertyuiopqsdfghjklmwxcvbn", "123"), None);