Rustdoc from stage N *minus* 1

Author: jyn514

src/building/stages.png

@@ -14,7 +14,7 @@
 Rows are things that can be used together to build a program.
 \\
 
-\noindent \verb|./x.py build --stage N| builds programs in \emph{column} \verb|N| (except rustdoc - it builds rustdoc from column \verb|N + 1|).\\
+\noindent \verb|./x.py build --stage N| builds programs in \emph{column} \verb|N| (except rustdoc - it builds rustdoc from column \verb|N - 1|).\\
 \noindent \verb|./x.py test --stage N| builds and tests everything in \emph{row} \verb|N|.\\
 \noindent \verb|./x.py doc --stage N| generates docs with rustdoc from \emph{row} \verb|N|.\\
 };