Replace colon with parentheses, add missing period

Author: tamird

library/core/src/bstr/mod.rs

@@ -36,7 +36,7 @@ use crate::ops::{Deref, DerefMut, DerefPure};
 /// presented as hex escape sequences.
 ///
 /// The `Display` implementation behaves as if the `ByteStr` were first lossily converted to a
-/// `str`, with invalid UTF-8 presented as the Unicode replacement character: �
+/// `str`, with invalid UTF-8 presented as the Unicode replacement character (�).
 #[unstable(feature = "bstr", issue = "134915")]
 #[repr(transparent)]
 #[doc(alias = "BStr")]