feat: make withWaitFindSnap consider all snaps of a document

src/Lean/Server/FileWorker/Utils.lean

@@ -58,6 +58,13 @@ structure EditableDocument where
   cancelTk   : CancelToken
   deriving Inhabited
 
+namespace EditableDocument
+
+def allSnaps (doc : EditableDocument) : AsyncList ElabTaskError Snapshot :=
+  AsyncList.cons doc.headerSnap doc.cmdSnaps
+
+end EditableDocument
+
 structure RpcSession where
   /-- Objects that are being kept alive for the RPC client, together with their type names,
   mapped to by their RPC reference.

src/Lean/Server/Requests.lean

@@ -96,7 +96,7 @@ def withWaitFindSnap (doc : EditableDocument) (p : Snapshot → Bool)
   (notFoundX : RequestM β)
   (x : Snapshot → RequestM β)
     : RequestM (RequestTask β) := do
-  let findTask ← doc.cmdSnaps.waitFind? p
+  let findTask ← doc.allSnaps.waitFind? p
   mapTask findTask fun
     /- The elaboration task that we're waiting for may be aborted if the file contents change.
     In that case, we reply with the `fileChanged` error. Thanks to this, the server doesn't