Merge pull request #1598 from XRPLF/oeggert/issue1554

Add code samples for markers and pagination.

content/_code-samples/markers-and-pagination/README.md

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+# Markers and Pagination
+
+Iterate over a `ledger_data` method request that requires multiple calls.
+
+Examples from the [Markers and Pagination page](https://xrpl.org/markers-and-pagination.html#markers-and-pagination).

content/_code-samples/markers-and-pagination/js/pagination-with-markers.js

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+const xrpl = require("xrpl")
+
+async function main() {
+
+  // Create a client and connect to the network.
+  const client = new xrpl.Client("wss://xrplcluster.com/")
+  await client.connect()
+
+  // Query the most recently validated ledger for info.
+  let ledger = await client.request({
+    "command": "ledger_data",
+    "ledger_index": "validated",
+  })
+  const ledger_data_index = ledger["result"]["ledger_index"]
+
+  // Create a function to run on each API call.
+  function printLedgerResult(){
+    console.log(ledger["result"])
+  }
+ 
+  // Execute function at least once before checking for markers.
+  do {
+    printLedgerResult()
+    
+    if (ledger["result"]["marker"] === undefined) {
+        break
+    }
+
+    // Specify the same ledger and add the marker to continue querying.
+    const ledger_marker = await client.request({
+        "command": "ledger_data",
+        "ledger_index": ledger_data_index,
+        "marker": ledger["result"]["marker"]
+    })
+    ledger = ledger_marker
+
+  } while (true)
+
+  // Disconnect when done. If you omit this, Node.js won't end the process.
+  client.disconnect()
+}
+
+main()

content/_code-samples/markers-and-pagination/py/pagination-with-markers.py

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+from xrpl.clients import JsonRpcClient
+from xrpl.models.requests import LedgerData
+
+# Create a client to connect to the network.
+client = JsonRpcClient("https://xrplcluster.com/")
+
+# Query the most recently validated ledger for info.
+ledger = LedgerData(ledger_index="validated")
+ledger_data = client.request(ledger).result
+ledger_data_index = ledger_data["ledger_index"]
+
+# Create a function to run on each API call.
+def printLedgerResult():
+    print(ledger_data)
+
+# Execute function at least once before checking for markers.
+while True:
+    printLedgerResult()
+    if "marker" not in ledger_data:
+        break
+    
+    # Specify the same ledger and add the marker to continue querying.
+    ledger_marker = LedgerData(ledger_index=ledger_data_index, marker=ledger_data["marker"])
+    ledger_data = client.request(ledger_marker).result