getTransactions incorrectly states startLedger as required

[janewang]

RPC Page: https://developers.stellar.org/docs/data/rpc/api-reference/methods/getTransactions

The documentation currently incorrectly indicates startLedger as always required. That is not correct.

startLedger and cursor cannot be sent at the same time. Either use startLedger or cursor. The docs should say something to this respect so it's clear how to data.

Maybe also add an example of using cursor instead of startLedger.

curl -X POST \
-H 'Content-Type: application/json' \
-d '{
  "jsonrpc": "2.0",
  "id": 8675309,
  "method": "getTransactions",
  "params": {
    "pagination": {
      "cursor": "3086346319040513",
      "limit": 5
    }
  }
}' \
https://soroban-testnet.stellar.org:443 | jq

[janewang]

I think the same issue in documentation also exists on getEvents https://developers.stellar.org/docs/data/rpc/api-reference/methods/getEvents

cc @mollykarcher