rust: error: Markdown style nit

This patch fixes a trivial markdown style nit in the `SAFETY` comment.

Signed-off-by: Manmohan Shukla <[email protected]>
Reviewed-by: Jianguo Bao <[email protected]>
Reviewed-by: Finn Behrens <[email protected]>
Reviewed-by: Benno Lossin <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Vincenzo Palazzo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: dymenshen

rust/kernel/error.rs

@@ -133,7 +133,7 @@ impl Error {
     /// Returns the error encoded as a pointer.
     #[allow(dead_code)]
     pub(crate) fn to_ptr<T>(self) -> *mut T {
-        // SAFETY: self.0 is a valid error due to its invariant.
+        // SAFETY: `self.0` is a valid error due to its invariant.
         unsafe { bindings::ERR_PTR(self.0.into()) as *mut _ }
     }