Change at:dejs-soft:format to reject too-long json arrays

`at` is for when you expect an array of a certain exact structure. If it
has extra elements, that indicates you were mistaken about the strucutre,
so it should fail to match.

bin/solid.pill

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:fff4813d3c7fbc2275d31f4d2385e6b9c9a6e10352dee4542d48ce9374f73216
-size 15793950
+oid sha256:1bc81ced700ac9bbe3a6d231ccdec06956abe48a023e147e56a1c9e7a02523d8
+size 12744827

pkg/arvo/sys/zuse.hoon

@@ -5836,6 +5836,7 @@
       |*  wil/(pole fist)
       |=  jon/json
       ?.  ?=({$a *} jon)  ~
+      ?.  =((lent wil) (lent p.jon))  ~
       =+  raw=((at-raw wil) p.jon)
       ?.((za raw) ~ (some (zp raw)))
     ::