apps: resolve style comments about ?- vs ?:

pkg/arvo/app/chat-cli.hoon

@@ -894,16 +894,14 @@
         =/  =uid:post    (snag index history)
         =/  =node:graph  (got-node:libgraph uid)
         =.  audience     resource.uid
-        ?-    -.post.node
-            %|  [~ state]
-            %&
+        ?:  ?=(%| -.post.node)
+          [~ state]
         :_  put-ses
         ^-  (list card)
         :~  (print:sh-out ['?' ' ' number])
             (effect:sh-out ~(render-activate mr resource.uid p.post.node))
             prompt:sh-out
         ==
-        ==
       --
     ::  +chats: display list of joined chats
     ::

pkg/arvo/app/graph-push-hook.hoon

@@ -300,10 +300,8 @@
   =/  parent-index=index:store
     (scag (dec (lent index)) index)
   ?:  (~(has by nodes) parent-index)  %.y
-  ?-  -.post.node
-    %|  %.n
-  ::
-      %&
+  ?:  ?=(%| -.post.node)
+    %.n
   ?.  =(author.p.post.node src.bowl)
     %.n
   =/  =permissions:store
@@ -318,11 +316,9 @@
         %self
       =/  parent-node=node:store
         (got-node:gra resource parent-index)
-        ?-  -.post.parent-node
-          %|  %.n
-          %&  =(author.p.post.parent-node src.bowl)
-        ==
-    ==
+      ?:  ?=(%| -.post.parent-node)
+        %.n
+      =(author.p.post.parent-node src.bowl)
   ==
 ::
 ++  is-allowed-remove
@@ -337,10 +333,7 @@
   ^-  ?
   =/  =node:store
     (got-node:gra resource index)
-  ?-  -.post.node
-    %|  %.n
-  ::
-      %&
+  ?:  ?=(%| -.post.node)  %.n
   =/  =permissions:store
     %^  remove-mark  resource  vip
     (node-to-indexed-post node)
@@ -351,7 +344,6 @@
     %no    %.n
     %self  =(author.p.post.node src.bowl)
   ==
-  ==
 ::
 ++  build-permissions
   |=  [=mark kind=?(%add %remove) mode=?(%sing %next)]

pkg/arvo/app/graph-store.hoon

@@ -368,11 +368,11 @@
           =/  =node:store
             ~|  "cannot remove index that does not exist {<index>}"
             (need (get:orm graph atom))
+          %_    node
+              post
             ~|  "cannot remove post that has already been removed"
             ?>  ?=(%& -.post.node)
             =*  p  p.post.node
-          %=    node
-              post
             ^-  maybe-post:store
             :-  %|
             ?~  hash.p