Auto merge of #111922 - vaporoxx:feat-searcher, r=dtolnay

feat: implement `DoubleEndedSearcher` for `CharArray[Ref]Searcher`

This PR implements `DoubleEndedSearcher` for both `CharArraySearcher` and `CharArrayRefSearcher`. I'm not sure whether this was just overlooked or if there is a reason for it, but since it behaves exactly like `CharSliceSearcher`, I think the implementations should be appropriate.

library/core/src/str/pattern.rs

@@ -806,6 +806,8 @@ unsafe impl<'a, const N: usize> ReverseSearcher<'a> for CharArraySearcher<'a, N>
     searcher_methods!(reverse);
 }
 
+impl<'a, const N: usize> DoubleEndedSearcher<'a> for CharArraySearcher<'a, N> {}
+
 /// Searches for chars that are equal to any of the [`char`]s in the array.
 ///
 /// # Examples
@@ -826,6 +828,8 @@ unsafe impl<'a, 'b, const N: usize> ReverseSearcher<'a> for CharArrayRefSearcher
     searcher_methods!(reverse);
 }
 
+impl<'a, 'b, const N: usize> DoubleEndedSearcher<'a> for CharArrayRefSearcher<'a, 'b, N> {}
+
 /////////////////////////////////////////////////////////////////////////////
 // Impl for &[char]
 /////////////////////////////////////////////////////////////////////////////