Move restored documentation into the zcashd book

doc/book/src/SUMMARY.md

@@ -3,14 +3,20 @@
 [zcashd](README.md)
 - [User Documentation](user.md)
   - [Platform Support](user/platform-support.md)
+  - [Wallet Backup](user/wallet-backup.md)
+  - [Shielding Coinbase Outputs](user/shield-coinbase.md)
+  - [Data Directory Structure](user/files.md)
   - [Metrics](user/metrics.md)
+  - [Using `zcashd` with Tor](user/tor.md)
+  - [Security Warnings](user/security-warnings.md)
   - [Deprecated Features](user/deprecation.md)
 - [Developer Documentation](dev.md)
+  - [DNS Seeders](dev/dnsseed-policy.md)
   - [Rust in `zcashd`](dev/rust.md)
-  - [Regtest tips and hints](dev/regtest.md)
+  - [Regtest Tips And Hints](dev/regtest.md)
   - [Platform Tier Policy](dev/platform-tier-policy.md)
   - [Deprecation Procedure](dev/deprecation.md)
 - [Design](design.md)
-  - [Chain state](design/chain-state.md)
-  - ["Coins" view](design/coins-view.md)
-  - [P2P data propagation](design/p2p-data-propagation.md)
+  - [Chain State](design/chain-state.md)
+  - ["Coins" View](design/coins-view.md)
+  - [P2P Data Propagation](design/p2p-data-propagation.md)