Update indentation in reference

doc/system/reference.adoc

@@ -54,12 +54,12 @@ the old names, but will provide them when the macro `BOOST_SYSTEM_ENABLE_DEPRECA
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    template<class T>
+template<class T>
   struct is_error_code_enum { static const bool value = false; };
 
-  } // namespace system
+} // namespace system
 } // namespace boost
 ```
 
@@ -74,12 +74,12 @@ be provided in the same namespace as the enumeration type.
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    template<class T>
+template<class T>
   struct is_error_condition_enum { static const bool value = false; };
 
-  } // namespace system
+} // namespace system
 } // namespace boost
 ```
 
@@ -94,9 +94,9 @@ should be provided in the same namespace as the enumeration type.
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    namespace errc {
+namespace errc {
   enum errc_t
   {
     success = 0,
@@ -180,15 +180,15 @@ namespace boost {
     wrong_protocol_type             //EPROTOTYPE
   };
 
-    } // namespace errc
+} // namespace errc
 
-    template<> struct is_error_condition_enum<errc::errc_t>
+template<> struct is_error_condition_enum<errc::errc_t>
   { static const bool value = true; };
 
-    constexpr error_code make_error_code( errc::errc_t e ) noexcept;
+constexpr error_code make_error_code( errc::errc_t e ) noexcept;
-    constexpr error_condition make_error_condition( errc::errc_t e ) noexcept;
+constexpr error_condition make_error_condition( errc::errc_t e ) noexcept;
 
-  } // namespace system
+} // namespace system
 } // namespace boost
 ```
 
@@ -268,23 +268,23 @@ errors in addition to those defined in Boost.System.
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    class error_category
+class error_category
-    {
+{
-    public: // noncopyable
+public: // noncopyable
 
     error_category( error_category const & ) = delete;
     error_category& operator=( error_category const & ) = delete;
 
-    protected:
+protected:
 
     ~error_category() = default;
 
     constexpr error_category() noexcept;
     explicit constexpr error_category( unsigned long long id ) noexcept;
 
-    public:
+public:
 
     virtual const char * name() const noexcept = 0;
 
@@ -311,13 +311,13 @@ namespace boost {
 
     operator std::error_category const & () const;
 
-    private:
+private:
 
     unsigned long long id_; // exposition only
+};
 
-    };
+} // namespace system
-  }
+} // namespace boost
-}
 ```
 
 #### Constructors
@@ -427,12 +427,16 @@ const char* my_category::message(int ev, char* buffer, size_t len) const noexcep
     case 0: return "no error";
     case 1: return "voltage out of range";
     case 2: return "impedance mismatch";
+
     case 31:
     case 32:
     case 33:
+
         std::snprintf(buffer, len, "component %d failure", ev-30);
         return buffer;
+
     default:
+
         std::snprintf(buffer, len, "unknown error %d", ev);
         return buffer;
     }
@@ -503,11 +507,11 @@ Returns: :: A reference to an `std::error_category` object corresponding
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    constexpr const error_category & system_category() noexcept;
+constexpr const error_category & system_category() noexcept;
 
-  } // namespace system
+} // namespace system
 } // namespace boost
 ```
 
@@ -526,11 +530,11 @@ Returns: :: A reference to a predefined `error_category` object identifying
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    constexpr const error_category & generic_category() noexcept;
+constexpr const error_category & generic_category() noexcept;
 
-  } // namespace system
+} // namespace system
 } // namespace boost
 ```
 
@@ -554,12 +558,12 @@ by exception.
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    class error_code {
+class error_code {
-    public:
+public:
 
-      // constructors:
+    // constructors
 
     constexpr error_code() noexcept;
     constexpr error_code( int val, const error_category & cat ) noexcept;
@@ -572,7 +576,7 @@ namespace boost {
 
     error_code( std::error_code const& ec ) noexcept;
 
-      // modifiers:
+    // modifiers
 
     constexpr void assign( int val, const error_category & cat ) noexcept;
 
@@ -584,7 +588,7 @@ namespace boost {
 
     constexpr void clear() noexcept;
 
-      // observers:
+    // observers
 
     constexpr int value() const noexcept;
     constexpr const error_category & category() const noexcept;
@@ -600,7 +604,7 @@ namespace boost {
     bool has_location() const noexcept;
     boost::source_location const & location() const noexcept;
 
-      // comparisons:
+    // comparisons
 
     friend constexpr bool operator==( const error_code & lhs,
       const error_code & rhs ) noexcept;
@@ -641,7 +645,7 @@ namespace boost {
     template<class E>
       friend constexpr bool operator!=( E lhs, const error_code & rhs ) noexcept;
 
-      // conversions:
+    // conversions
 
     operator std::error_code() const;
     operator std::error_code();
@@ -651,19 +655,19 @@ namespace boost {
 
     std::string to_string() const;
 
-      // stream insertion:
+    // stream insertion
 
     template <class charT, class traits>
-        std::basic_ostream<charT, traits>&
+      friend std::basic_ostream<charT, traits>&
         operator<<( basic_ostream<charT, traits>& os, const error_code & ec );
-    };
+};
 
-    // non-member functions
+// non-member functions
 
-    std::size_t hash_value( const error_code & ec );
+std::size_t hash_value( const error_code & ec );
 
-  }
+} // namespace system
-}
+} // namespace boost
 ```
 
 #### Constructors
@@ -1034,12 +1038,12 @@ Returns: :: If `ec` wraps a `std::error_code` object `e2`, `std::hash<std::error
 
 ```
 namespace boost {
-  namespace system {
+namespace system {
 
-    class error_condition {
+class error_condition {
-    public:
+public:
 
-      // constructors:
+    // constructors
 
     constexpr error_condition() noexcept;
     constexpr error_condition( int val, const error_category & cat ) noexcept;
@@ -1047,7 +1051,7 @@ namespace boost {
     template <class ErrorConditionEnum>
       constexpr error_condition( ErrorConditionEnum e ) noexcept;
 
-      // modifiers:
+    // modifiers
 
     constexpr void assign( int val, const error_category & cat ) noexcept;
 
@@ -1056,7 +1060,7 @@ namespace boost {
 
     constexpr void clear() noexcept;
 
-      // observers:
+    // observers
 
     constexpr int value() const noexcept;
     constexpr const error_category & category() const noexcept;
@@ -1067,7 +1071,7 @@ namespace boost {
     constexpr bool failed() const noexcept;
     constexpr explicit operator bool() const noexcept;
 
-      // comparisons:
+    // comparisons
 
     friend constexpr bool operator==( const error_condition & lhs,
       const error_condition & rhs ) noexcept;
@@ -1088,18 +1092,19 @@ namespace boost {
     friend bool operator!=( const error_condition & condition,
       const std::error_code & code ) noexcept;
 
-      // conversions:
+    // conversions
 
     operator std::error_condition() const;
 
-      // stream insertion:
+    // stream insertion
 
     template <class charT, class traits>
-        std::basic_ostream<charT, traits>&
+      friend std::basic_ostream<charT, traits>&
         operator<<( basic_ostream<charT, traits>& os, const error_condition & en );
-    };
+};
-  }
+
-}
+} // namespace system
+} // namespace boost
 ```
 
 #### Constructors
@@ -1295,7 +1300,7 @@ Returns: ::
 
 ## <boost/system/{zwsp}system_error.hpp>
 
-### Class system_error
+### system_error
 
 The class `system_error` describes an exception object used to
 report errors that have an associated `error_code`. Such errors
@@ -1303,13 +1308,12 @@ typically originate from operating system or other low-level
 application program interfaces.
 
 ```
-namespace boost
+namespace boost {
+namespace system {
+
+class system_error: public std::runtime_error
 {
-  namespace system
+public:
-  {
-    class system_error: public std::runtime_error
-    {
-    public:
 
     explicit system_error( error_code ec );
     system_error( error_code ec, const char * what_arg );
@@ -1323,9 +1327,10 @@ namespace boost
 
     error_code code() const noexcept;
     const char * what() const noexcept;
-    };
+};
-  }
+
-}
+} // namespace system
+} // namespace boost
 ```
 
 #### Constructors