Correct and clarify integer division rounding docs

Author: wthrowe

src/libcore/num/mod.rs

@@ -459,15 +459,15 @@ macro_rules! int_impl {
             }
         }
 
-        /// Wrapping (modular) division. Computes `floor(self / other)`,
+        /// Wrapping (modular) division. Computes `self / other`,
         /// wrapping around at the boundary of the type.
         ///
         /// The only case where such wrapping can occur is when one
         /// divides `MIN / -1` on a signed type (where `MIN` is the
         /// negative minimal value for the type); this is equivalent
         /// to `-MIN`, a positive value that is too large to represent
         /// in the type. In such a case, this function returns `MIN`
-        /// itself..
+        /// itself.
         #[stable(feature = "num_wrapping", since = "1.2.0")]
         #[inline(always)]
         pub fn wrapping_div(self, rhs: Self) -> Self {
@@ -1031,15 +1031,15 @@ macro_rules! uint_impl {
             }
         }
 
-        /// Wrapping (modular) division. Computes `floor(self / other)`,
+        /// Wrapping (modular) division. Computes `self / other`,
         /// wrapping around at the boundary of the type.
         ///
         /// The only case where such wrapping can occur is when one
         /// divides `MIN / -1` on a signed type (where `MIN` is the
         /// negative minimal value for the type); this is equivalent
         /// to `-MIN`, a positive value that is too large to represent
         /// in the type. In such a case, this function returns `MIN`
-        /// itself..
+        /// itself.
         #[stable(feature = "num_wrapping", since = "1.2.0")]
         #[inline(always)]
         pub fn wrapping_div(self, rhs: Self) -> Self {

src/libcore/ops.rs

@@ -315,6 +315,9 @@ mul_impl! { usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 }
 
 /// The `Div` trait is used to specify the functionality of `/`.
 ///
+/// For primitive integral types, this operation rounds towards zero,
+/// truncating any fractional part of the exact result.
+///
 /// # Examples
 ///
 /// A trivial implementation of `Div`. When `Foo / Foo` happens, it ends up
@@ -369,6 +372,9 @@ div_impl! { usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 }
 
 /// The `Rem` trait is used to specify the functionality of `%`.
 ///
+/// For primitive integral types, this operation satisfies `n % d == n
+/// - (n / d) * d`.  The result has the same sign as the left operand.
+///
 /// # Examples
 ///
 /// A trivial implementation of `Rem`. When `Foo % Foo` happens, it ends up