Fix assembly example

examples/assembly.janet

@@ -1,10 +1,10 @@
 # Example of dst bytecode assembly
 
 # Fibonacci sequence, implemented with naive recursion.
-(def fibasm (asm '{
-  arity 1
-  bytecode [
-    (ltim 1 0 0x2)      # $1 = $0 < 2
+(def fibasm
+  (asm
+    '{:arity 1
+      :bytecode @[(ltim 1 0 0x2) # $1 = $0 < 2
                   (jmpif 1 :done) # if ($1) goto :done
                   (lds 1) # $1 = self
                   (addim 0 0 -0x1) # $0 = $0 - 1
@@ -16,8 +16,7 @@
                   (add 0 0 2) # $0 = $0 + $2 (integers)
                   :done
                   (ret 0) # return $0
-  ]
-}))
+]}))
 
 # Test it