pgindent: document location of "all" typedef lists

src/tools/pgindent/README

@@ -22,6 +22,8 @@ This can format all PostgreSQL *.c and *.h files, but excludes *.y, and
 
 	wget -O src/tools/pgindent/typedefs.list http://buildfarm.postgresql.org/cgi-bin/typedefs.pl
 
+   (see http://www.pgbuildfarm.org/cgi-bin/typedefs.pl?show_list for a full list of typedefs)
+
 6) Run pgindent:
 
 	src/tools/pgindent/pgindent