design/tpl: Vector addition example: \bicomp{=>i}

The example as presented was incorrect, since \bicomp is undefined for
scalar values.

design/tpl/sec/notation.tex

@@ -360,7 +360,7 @@ Since a vector is a function,
 We can also add two vectors, and scale them:
 
 \begin{align*}
-  1 \bicomp{+} \Vector{1,2,3} \bicomp{+} \Vector{4,5,6}
+  1 \bicompi{+} \Vector{1,2,3} \bicompi{+} \Vector{4,5,6}
     &= \Vector{1+1,\, 2+1,\, 3+1} \bicomp{+} \Vector{4,5,6} \\
     &= \Vector{2,3,4} \bicomp{+} \Vector{4,5,6} \\
     &= \Vector{2+4,\, 3+5,\, 4+6} \\