Update documentation

doc/array/reference.adoc

@@ -35,6 +35,9 @@ namespace boost {
   template<typename T, std::size_t N>
     constexpr bool operator>=(const array<T, N>&, const array<T, N>&);
 
+  template<typename T, std::size_t N>
+    constexpr auto operator<=>(const array<T, N>&, const array<T, N>&);
+
   template<std::size_t Idx, typename T, std::size_t N>
     constexpr T& get(array<T, N>&) noexcept;
   template<std::size_t Idx, typename T, std::size_t N>
@@ -136,7 +139,7 @@ public:
 template<typename U> array& operator=(const array<U, N>& other);
 ```
 [horizontal]
-Effects: :: `std::copy(rhs.begin(), rhs.end(), begin())`.
+Effects: :: For each `i` in `[0..N)`, performs `elems[i] = other.elems[i];`.
 
 ---
 
@@ -233,7 +236,7 @@ constexpr const_reference operator[](size_type i) const;
 [horizontal]
 Requires: :: `i < N`.
 Returns: ::  `elems[i]`.
-Throws: :: nothing.
+Throws: :: Nothing.
 
 ---
 
@@ -254,7 +257,7 @@ constexpr const_reference front() const;
 [horizontal]
 Requires: ::  `N > 0`.
 Returns: :: `elems[0]`.
-Throws: :: nothing.
+Throws: :: Nothing.
 
 ---
 
@@ -265,7 +268,7 @@ constexpr const_reference back() const;
 [horizontal]
 Requires: :: `N > 0`.
 Returns: :: `elems[N-1]`.
-Throws: :: nothing.
+Throws: :: Nothing.
 
 ---
 
@@ -302,7 +305,7 @@ Complexity: :: linear in `N`.
 void fill(const T& value);
 ```
 [horizontal]
-Effects: :: for each `i` in `[0..N)`, performs `elems[i] = value;`.
+Effects: :: For each `i` in `[0..N)`, performs `elems[i] = value;`.
 
 ---
 
@@ -382,6 +385,17 @@ Returns: :: `!(x < y)`.
 
 ---
 
+```
+template<typename T, std::size_t N>
+  constexpr auto operator<=>(const array<T, N>& x, const array<T, N>& y)
+  -> decltype(x[0] <=> y[0]);
+```
+[horizontal]
+Effects: :: For each `i` in `[0..N)`, if `(x[i] \<\=> y[i]) != 0`, returns `x[i] \<\=> y[i]`. Otherwise, returns `std::strong_ordering::equal`, converted to the return type.
+Remarks: :: When `N` is 0, the return type is `std::strong_ordering` and the return value is `std::strong_ordering::equal`.
+
+---
+
 ### Specializations
 
 ```