Optimize multi-char string patterns

Author: yotamofek

library/core/src/slice/cmp.rs

@@ -282,4 +282,4 @@ macro_rules! impl_slice_contains {
     };
 }
 
-impl_slice_contains!(u16, u32, u64, i16, i32, i64, f32, f64, usize, isize);
+impl_slice_contains!(u16, u32, u64, i16, i32, i64, f32, f64, usize, isize, char);

library/core/src/str/pattern.rs

@@ -644,21 +644,21 @@ where
 impl<const N: usize> MultiCharEq for [char; N] {
     #[inline]
     fn matches(&mut self, c: char) -> bool {
-        self.iter().any(|&m| m == c)
+        self.contains(&c)
     }
 }
 
 impl<const N: usize> MultiCharEq for &[char; N] {
     #[inline]
     fn matches(&mut self, c: char) -> bool {
-        self.iter().any(|&m| m == c)
+        self.contains(&c)
     }
 }
 
 impl MultiCharEq for &[char] {
     #[inline]
     fn matches(&mut self, c: char) -> bool {
-        self.iter().any(|&m| m == c)
+        self.contains(&c)
     }
 }