refactor(solutions/delete_prefix): simpler code using built-in method

Author: sadiqui

solutions/delete_prefix/src/lib.rs

@@ -8,17 +8,7 @@
 // delete_prefix("not", "win");
 
 pub fn delete_prefix<'a, 'b>(prefix: &'b str, s: &'a str) -> Option<&'a str> {
-    if prefix.len() > s.len() {
-        return None;
-    }
-    let mut char_s = s.chars();
-
-    for char_prefix in prefix.chars() {
-        if char_prefix != char_s.next()? {
-            return None;
-        }
-    }
-    Some(&s[prefix.len()..])
+    s.strip_prefix(prefix)
 }
 
 #[cfg(test)]