gui/wallet: name backups by backend, and stop saying "wallet.dat" for phrase gaps

Two things that read wrong once the wallet is on SQLite:

- The Wallet Safety backup dialog defaulted the file name to .dat, but
  BackupWallet copies wallet.sqlite under the SQLite backend -- so the
  suggested name put SQLite contents in a wallet-backup-*.dat file. The
  default now matches the live backend (.sqlite on SQLite, .dat on BDB).

- The recovery audit called coins on non-phrase keys "wallet.dat-only" and
  told the user to "keep wallet.dat backups". Under SQLite those coins live
  in wallet.sqlite, not wallet.dat. Reworded to the backend-neutral truth:
  "not phrase-backed" balance, and "keep a file backup of this wallet" --
  accurate on either backend. Same wording in the CLI -recoveryaudit and
  the GUI Wallet Safety panel.

Display/naming only; audit numbers and BackupWallet are unchanged. All 13
wallet suites still pass.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/walletcmd.cpp b/src/walletcmd.cpp
index 1f1fd27..f59fc0c 100644
--- a/src/walletcmd.cpp
+++ b/src/walletcmd.cpp
@@ -429,13 +429,13 @@ int CmdRecoveryAudit()
     }
     printf("  covered by recovery phrase:   %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nRecoverableCredit).c_str(), audit.nRecoverableTx);
-    printf("  wallet.dat-only balance:      %s BTF (%d transaction(s))\n",
+    printf("  not phrase-backed balance:    %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nLegacyCredit).c_str(), audit.nLegacyTx);
     printf("  immature mining rewards:      %s BTF\n", FormatMoney(nImmatureTotal).c_str());
     printf("    phrase-backed immature:     %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nRecoverableImmatureCredit).c_str(),
            audit.nRecoverableImmatureTx);
-    printf("    wallet.dat-only immature:   %s BTF (%d transaction(s))\n",
+    printf("    not phrase-backed immature: %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nLegacyImmatureCredit).c_str(),
            audit.nLegacyImmatureTx);
 
@@ -457,7 +457,7 @@ int CmdRecoveryAudit()
     {
         printf("\n");
         printf("Warning: some coins are on keys the phrase does not reproduce.\n");
-        printf("Keep wallet.dat backups until that balance has been moved to a phrase-backed address.\n");
+        printf("Keep a file backup of this wallet until that balance has been moved to a phrase-backed address.\n");
         fflush(stdout);
         return 2;
     }