fs: jbd2: escape a string with special chars on a kernel-doc

kernel-doc will try to interpret a foo() string, except if
properly escaped.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

fs/jbd2/transaction.c

@@ -1066,10 +1066,10 @@ out:
  * @handle: transaction to add buffer modifications to
  * @bh:     bh to be used for metadata writes
  *
- * Returns an error code or 0 on success.
+ * Returns: error code or 0 on success.
  *
  * In full data journalling mode the buffer may be of type BJ_AsyncData,
- * because we're write()ing a buffer which is also part of a shared mapping.
+ * because we're ``write()ing`` a buffer which is also part of a shared mapping.
  */
 
 int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)