fix typos

defs.tex

@@ -42,7 +42,7 @@
 \newcommand{\IF}[3]{\key{(If}\,#1\;#2\;#3\key{)}}
 \newcommand{\VECTOR}[1]{\key{(Prim}\;\code{'vector}\;\code{(list}\;#1^{*}\code{))}}
 \newcommand{\VECREF}[2]{\key{(Prim}\;\code{'vector-ref}\;\code{(list}\;#1\;#2\code{))}}
-\newcommand{\VECSET}[3]{\key{(Prim}\;\code{'vector-set}\;\code{(list}\;#1\;#2\;#3\code{))}}
+\newcommand{\VECSET}[3]{\key{(Prim}\;\code{'vector-set!}\;\code{(list}\;#1\;#2\;#3\code{))}}
 \newcommand{\VOID}[1]{\key{(Void)}}
 \newcommand{\APPLY}[2]{\key{(Apply}\;#1\;#2\code{)}}
 \newcommand{\FUNDEF}[5]{\key{(Def}~#1~#2~#3~#4~#5\code{)}}