Fix Writer exemplar in docs

doc/design.qbk

@@ -29,8 +29,8 @@ libraries:
 
 * Role-symmetric interfaces; client and server the same (or close to it).
 
-* Leave important decisions to the user, such as
-  allocating memory or managing flow control.
+* Leave important decisions such as allocating memory or
+  managing flow control, to the user.
 
 Beast uses the __DynamicBuffer__ concept presented in the Networking TS
 (__N4588__), and relies heavily on the Boost.Asio __ConstBufferSequence__

doc/master.qbk

@@ -50,7 +50,7 @@ provides implementations of the HTTP and WebSocket protocols.
   [[
     [link beast.overview Overview]
   ][
-    An introduction wsth features, requirements, and credits.
+    An introduction with features, requirements, and credits.
   ]]
   [[
     [link beast.http Using HTTP]

doc/types/Parser.qbk

@@ -30,7 +30,7 @@ In this table:
     [`a.complete()`]
     [`bool`]
     [
-        Returns `true` when the parser is complete.
+        Returns `true` when parsing is complete.
     ]
 ]
 [

doc/types/Writer.qbk

@@ -128,8 +128,8 @@ public:
         use chunk-encoding or terminate the connection to indicate the end
         of the message.
     */
-    std::size_t
-    content_length() const;
+    std::uint64_t
+    content_length();
 
     /** Write zero or one buffer representing the message body.