refactor(lib): replace deprecated numeric api with primitive one

Author: tottoto

src/header/map.rs

@@ -1066,7 +1066,7 @@ impl<T> HeaderMap<T> {
         } else {
             ValueIter {
                 map: self,
-                index: ::std::usize::MAX,
+                index: usize::MAX,
                 front: None,
                 back: None,
             }

src/uri/mod.rs

@@ -28,9 +28,9 @@ use std::convert::TryFrom;
 use bytes::Bytes;
 
 use std::error::Error;
+use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::str::{self, FromStr};
-use std::{fmt, u16, u8};
 
 use self::scheme::Scheme2;
 

src/uri/path.rs

@@ -14,7 +14,7 @@ pub struct PathAndQuery {
     pub(super) query: u16,
 }
 
-const NONE: u16 = ::std::u16::MAX;
+const NONE: u16 = u16::MAX;
 
 impl PathAndQuery {
     // Not public while `bytes` is unstable.