docs: add request batching example (#404)

Adds an example for batching JSON-RPC requests

Author: sarahschwartz

content/20.zksync-protocol/10.api/10.conventions.md

@@ -22,6 +22,7 @@ Here are some examples:
 - WRONG: ff (must be prefixed 0x)
 
 ### Unformatted data
+
 When encoding unformatted data (byte arrays, account addresses, hashes, bytecode arrays):
 encode as hex, prefix with "0x", two hex digits per byte.
 
@@ -55,3 +56,30 @@ The following options are possible for the defaultBlock parameter:
 - String "safe" - for the latest safe head block
 - String "finalized" - for the latest finalized block
 - String "pending" - for the pending state/transactions
+
+## Batching JSON-RPC Requests
+
+JSON-RPC requests can be batched together.
+
+Example batched request:
+
+```bash
+curl https://sepolia.era.zksync.dev -X POST -H "Content-Type: application/json" --data '[{"jsonrpc": "2.0", "id": 1, "method": "eth_estimateGas", "params": [{"from": "0x03AC0b1b952C643d66A4Dc1fBc75118109cC074C"}]},{"jsonrpc": "2.0", "id": 2, "method": "eth_gasPrice", "params": []}]' | jq
+```
+
+Example response:
+
+```bash
+[
+  {
+    "jsonrpc": "2.0",
+    "result": "0x9dfe4",
+    "id": 1
+  },
+  {
+    "jsonrpc": "2.0",
+    "result": "0x17d7840",
+    "id": 2
+  }
+]
+```