Add missing preamble to pgfmanual-en-base-scopes.tex

doc/generic/pgf/pgfmanual-en-base-scopes.tex

@@ -416,7 +416,7 @@ \subsubsection{The Main Environment}
     This command also specifies the baseline indirectly, but the $y$-coordinate
     of the given \meta{point} is only computed at the end of the picture.
     %
-\begin{codeexample}[]
+\begin{codeexample}[preamble={\usetikzlibrary{shapes.misc}}]
 Hello
 \begin{pgfpicture}
   \pgfsetbaselinepointlater{\pgfpointanchor{X}{base}}