Re-level non-docs content to top of repo and rename content→docs

docs/references/protocol/ledger-data/index.md

@@ -0,0 +1,22 @@
+---
+html: ledger-data-formats.html
+parent: protocol-reference.html
+seo:
+    description: Learn about individual entries that comprise the XRP Ledger's shared state data.
+metadata:
+  indexPage: true
+---
+# Ledger Data Formats
+
+Each [ledger version](../../../concepts/ledgers/index.md) in the XRP Ledger is made up of three parts:
+
+- **[Ledger Header](ledger-header.md)**: Data about this ledger version itself.
+- **[Transaction Set](../transactions/index.md)**: The transactions that were executed to create this ledger version.
+- **[State Data](ledger-entry-types/index.md)**: A list of ledger entries, representing all accounts, settings, and balances as of this ledger version. (This is also called the "account state".)
+
+## State Data
+
+{% partial file="/_snippets/ledger-objects-intro.md" /%}
+
+{% child-pages /%}
+