docs: minor fixes

doc/28_ref_optional_semantics.qbk

@@ -2,6 +2,7 @@
     Boost.Optional
 
     Copyright (c) 2003-2007 Fernando Luis Cacciola Carballal
+    Copyright (C) 2014 - 2026 Andrzej Krzemieński.
 
     Distributed under the Boost Software License, Version 1.0.
     (See accompanying file LICENSE_1_0.txt or copy at
@@ -25,24 +26,22 @@ __SPACE__
 
 [: `constexpr optional<T>::optional() noexcept;`]
 
-* [*Effect:] Default-Constructs an `optional`.
-* [*Postconditions:] `*this` is [_uninitialized].
-* [*Notes:] T's default constructor [_is not] called.
+* [*Postconditions:] `*this` does ['not] contain a value (is "uninitialized").
+* [*Remarks:] No contained value is initialized. For every object type `T` these constructors are core constant expressions.
 * [*Example:]
 ``
-optional<T> def ;
-assert ( !def ) ;
+optional<T> oN ;
+assert ( !oN ) ;
 ``
 
 __SPACE__
 
-[#reference_optional_constructor_none_t]
 
+[#reference_optional_constructor_none_t]
 [: `constexpr optional<T>::optional( none_t ) noexcept;`]
 
-* [*Effect:] Constructs an `optional` uninitialized.
-* [*Postconditions:] `*this` is [_uninitialized].
-* [*Notes:] `T`'s default constructor [_is not] called. The expression
+* [*Postconditions:] `*this` does ['not] contain a value (is "uninitialized").
+* [*Remarks:] No contained value is initialized. For every object type `T` these constructors are core constant expressions. The expression
 `boost::none` denotes an instance of `boost::none_t` that can be used as
 the parameter.
 * [*Example:]

doc/91_comparison_with_std.qbk

@@ -47,6 +47,17 @@
   `std::ranges::find(rng, boost::none)`] [`std::vector<optional<int>> rng;`
 
   `std::ranges::find(rng, boost::optional<int>{})`] [optional<T> is never [@https://en.cppreference.com/w/cpp/concepts/equality_comparable `std::equality_comparable_with`] `nullopt_t` in `std`. ] ]
+
+  [ [```
+  void test(vector<optional<T>> rng, T val) {
+    std::ranges::find(rng, val);
+  }
+  ```] [```
+  void test(vector<optional<T>> rng, T val) {
+    std::ranges::find(rng, make_optional(val));
+  }
+  ```] [The same code for `std::optional` compiles but is ['undefined behavior] when `T` is itself an `optional`. ] ]
+
 ]
 
 

doc/92_relnotes.qbk

@@ -18,7 +18,7 @@
   `constexpr` support:
 
     * In C++11, some constructors and `const`-qualified accessors become usable
-      in compile-time contexts (are ['core constant expressions] for types
+      in compile-time contexts (are ['core constant expressions]) for types
       satisfying certain constraints.
     * In C++14 even some mutating operations become core constant expressions (those
       that do not require changing the state of `optional` from not having a value to