rollup merge of #23549: aturon/stab-num

This commit stabilizes the `std::num` module:

* The `Int` and `Float` traits are deprecated in favor of (1) the
  newly-added inherent methods and (2) the generic traits available in
  rust-lang/num.

* The `Zero` and `One` traits are reintroduced in `std::num`, which
  together with various other traits allow you to recover the most
  common forms of generic programming.

* The `FromStrRadix` trait, and associated free function, is deprecated
  in favor of inherent implementations.

* A wide range of methods and constants for both integers and floating
  point numbers are now `#[stable]`, having been adjusted for integer
  guidelines.

* `is_positive` and `is_negative` are renamed to `is_sign_positive` and
  `is_sign_negative`, in order to address #22985

* The `Wrapping` type is moved to `std::num` and stabilized;
  `WrappingOps` is deprecated in favor of inherent methods on the
  integer types, and direct implementation of operations on
  `Wrapping<X>` for each concrete integer type `X`.

Closes #22985
Closes #21069

[breaking-change]

r? @alexcrichton

src/test/compile-fail/lint-dead-code-4.rs

@@ -16,8 +16,6 @@
 
 extern crate libc;
 
-use std::num::Int;
-
 struct Foo {
     x: usize,
     b: bool, //~ ERROR: struct field is never used

src/test/compile-fail/range-1.rs

@@ -15,9 +15,10 @@ pub fn main() {
     let _ = 0u32..10i32;
     //~^ ERROR start and end of range have incompatible types
 
-    // Float => does not implement iterator.
-    for i in 0f32..42f32 {}
-    //~^ ERROR the trait `core::num::Int` is not implemented for the type `f32`
+    // Bool => does not implement iterator.
+    for i in false..true {}
+    //~^ ERROR the trait
+    //~^^ ERROR the trait
 
     // Unsized type.
     let arr: &[_] = &[1, 2, 3];

src/test/run-pass/generic-extern-mangle.rs

@@ -12,11 +12,11 @@
 
 #![feature(core)]
 
-use std::num::Int;
+use std::ops::Add;
 
-extern "C" fn foo<T: WrappingOps>(a: T, b: T) -> T { a.wrapping_add(b) }
+extern "C" fn foo<T: Add>(a: T, b: T) -> T::Output { a + b }
 
 fn main() {
-    assert_eq!(99u8, foo(255u8, 100u8));
-    assert_eq!(99u16, foo(65535u16, 100u16));
+    assert_eq!(100u8, foo(0u8, 100u8));
+    assert_eq!(100u16, foo(0u16, 100u16));
 }