Add concepts section to docs.

doc/concepts.qbk

@@ -0,0 +1,10 @@
+[/
+ / Distributed under the Boost Software License, Version 1.0. (See accompanying
+ / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ /]
+
+[section Concepts]
+
+[all_concepts]
+
+[endsect]

doc/parser.qbk

@@ -149,6 +149,7 @@
 [include intro.qbk]
 [include tutorial.qbk]
 [include examples.qbk]
+[include concepts.qbk]
 
 [section Compiler Support]
 

include/boost/parser/concepts.hpp

@@ -28,6 +28,7 @@
 
 namespace boost { namespace parser {
 
+    //[ all_concepts
     template<typename T>
     concept utf8_code_unit = std::integral<T> && sizeof(T) == 1;
 
@@ -96,8 +97,6 @@ namespace boost { namespace parser {
         std::declval<detail::nope &>(),
         std::declval<detail::symbol_table_tries_t &>()));
 
-    // clang-format off
-
     template<typename T, typename I, typename S, typename GlobalState>
     concept error_handler =
         requires (
@@ -114,7 +113,7 @@ namespace boost { namespace parser {
             t.diagnose(kind, message, context);
         };
 
-//[ container_concept
+    //[ container_concept
     template<typename T>
     concept container = std::ranges::common_range<T> && requires(T t) {
         { t.insert(t.begin(), *t.begin()) }
@@ -122,7 +121,9 @@ namespace boost { namespace parser {
         { t.insert(t.begin(), t.begin(), t.end()) }
             -> std::same_as<std::ranges::iterator_t<T>>;
     };
-//]
+    //]
+
+    //]
 
     namespace detail {
 
@@ -132,8 +133,6 @@ namespace boost { namespace parser {
 
     }
 
-    // clang-format on
-
 }}
 
 #endif