docs: remove not existing key from block search query (backport #3399) (

#3408)

Closes #3266



---

#### PR checklist

- [ ] ~~Tests written/updated~~
- [ ] ~~Changelog entry added in `.changelog` (we use
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- [x] Updated relevant documentation (`docs/` or `spec/`) and code
comments
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<hr>This is an automatic backport of pull request #3399 done by
[Mergify](https://mergify.com).

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

docs/guides/app-dev/indexing-transactions.md

@@ -260,7 +260,7 @@ You can query for a paginated set of blocks by their events by calling the
 `/block_search` RPC endpoint:
 
 ```bash
-curl "localhost:26657/block_search?query=\"block.height > 10 AND val_set.num_changed > 0\""
+curl "localhost:26657/block_search?query=\"block.height > 10\""
 ```
 
 

rpc/openapi/openapi.yaml

@@ -966,7 +966,7 @@ paths:
           required: true
           schema:
             type: string
-            example: '"block.height > 1000 AND valset.changed > 0"'
+            example: '"block.height > 1000"'
         - in: query
           name: page
           description: "Page number (1-based)"