patch 8.1.0838: compiler warning for type conversion

Problem:    Compiler warning for type conversion.
Solution:   Add a type cast. (Mike Williams)

Author: brammool

src/channel.c

@@ -90,7 +90,7 @@ fd_write(sock_T fd, char *buf, size_t len)
 	if (todo > MAX_NAMED_PIPE_SIZE)
 	    size = MAX_NAMED_PIPE_SIZE;
 	else
-	    size = todo;
+	    size = (DWORD)todo;
 	// If the pipe overflows while the job does not read the data, WriteFile
 	// will block forever. This abandons the write.
 	memset(&ov, 0, sizeof(ov));

src/version.c

@@ -783,6 +783,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    838,
 /**/
     837,
 /**/