style: Make clippy happy

src/report.rs

@@ -7,7 +7,6 @@ use backtrace::Backtrace;
 use serde_derive::Serialize;
 use std::error::Error;
 use std::fmt::Write as FmtWrite;
-use std::mem;
 use std::{env, fs::File, io::Write, path::Path, path::PathBuf};
 use uuid::Uuid;
 
@@ -51,7 +50,7 @@ impl Report {
         const SKIP_FRAMES_NUM: usize = 8;
         //We take padding for address and extra two letters
         //to pad after index.
-        const HEX_WIDTH: usize = mem::size_of::<usize>() + 2;
+        const HEX_WIDTH: usize = size_of::<usize>() + 2;
         //Padding for next lines after frame's address
         const NEXT_SYMBOL_PADDING: usize = HEX_WIDTH + 6;