Merge bitcoin/bitcoin#35076: doc: clarify pruning impact on wallet sync

51ee8ca168 doc: clarify pruning impact on wallet sync (Memetic Money)

Pull request description:

  This updates prune-related help text to document the existing caveat that wallets should remain loaded, and relevant indexes should remain active, while pruning is enabled. This follows the behavior discussed in #30671 without changing startup, pruning, wallet, or index behavior.

  Refs #30671.

  Testing:
  - `cmake -S . -B build -DBUILD_GUI=OFF -DBUILD_TESTS=OFF -DBUILD_BENCH=OFF -DBUILD_FUZZ_BINARY=OFF -DENABLE_IPC=OFF -DCMAKE_PREFIX_PATH=/opt/homebrew`
  - `cmake --build build --target bitcoind -j$(sysctl -n hw.ncpu)`
  - `./build/bin/bitcoind -help 2>&1 | rg -A10 -- '-prune=<n>'`
  - `xmllint --noout src/qt/forms/optionsdialog.ui`
  - `git diff --check`

ACKs for top commit:
  achow101:
    ACK 51ee8ca168
  willcl-ark:
    ACK 51ee8ca168

Tree-SHA512: 0705947909d194aaa82142528150cf14f9f4e0569790ea1a8b0ccd2850aa632f65234d44ac5a800a623412f20732b124e7af77e62f335d64dc8b363b144fca92

src/init.cpp

@@ -547,7 +547,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-pid=<file>", strprintf("Specify pid file. Relative paths will be prefixed by a net-specific datadir location. (default: %s)", BITCOIN_PID_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-prune=<n>", strprintf("Reduce storage requirements by enabling pruning (deleting) of old blocks. This allows the pruneblockchain RPC to be called to delete specific blocks and enables automatic pruning of old blocks if a target size in MiB is provided. This mode is incompatible with -txindex. "
-            "Warning: Reverting this setting requires re-downloading the entire blockchain. "
+            "Warning: Reverting this setting requires re-downloading the entire blockchain. Wallets and indexes should be loaded at startup and kept active while pruning is enabled so they stay synchronized before old block data is deleted; wallets or indexes that fall behind pruned data may require a reindex. "
             "(default: 0 = disable pruning blocks, 1 = allow manual pruning via RPC, >=%u = automatically prune block files to stay under the specified target size in MiB)", MIN_DISK_SPACE_FOR_BLOCK_FILES / 1_MiB), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-reindex", "If enabled, wipe chain state and block index, and rebuild them from blk*.dat files on disk. Also wipe and rebuild other optional indexes that are active. If an assumeutxo snapshot was loaded, its chainstate will be wiped as well. The snapshot can then be reloaded via RPC.", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-reindex-chainstate", "If enabled, wipe chain state, and rebuild it from blk*.dat files on disk. If an assumeutxo snapshot was loaded, its chainstate will be wiped as well. The snapshot can then be reloaded via RPC.", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);

src/qt/forms/optionsdialog.ui

@@ -55,7 +55,7 @@
          <item>
           <widget class="QCheckBox" name="prune">
            <property name="toolTip">
-            <string>Enabling pruning significantly reduces the disk space required to store transactions. All blocks are still fully validated. Reverting this setting requires re-downloading the entire blockchain.</string>
+            <string>Enabling pruning significantly reduces the disk space required to store transactions. All blocks are still fully validated. Wallets should be loaded at startup and kept active while pruning is enabled so they stay synchronized before old block data is deleted; wallets that fall behind pruned data may require a reindex. Reverting this setting requires re-downloading the entire blockchain.</string>
            </property>
            <property name="text">
             <string>Prune &amp;block storage to</string>