Merge bitcoin/bitcoin#29254: log: Don't use scientific notation in log messages

c819a83 Don't use scientific notation in log messages (Kristaps Kaupe)

Pull request description:

  Don't see any benefits here, only harder to read for most of the users.

  Before:
  ```
  2024-01-16T13:11:36Z Dumped mempool: 8.165e-06s to copy, 0.00224268s to dump
  ```

  After:
  ```
  2024-01-16T13:11:36Z Dumped mempool: 0.000s to copy, 0.002s to dump
  ```

ACKs for top commit:
  kristapsk:
    > > > > lgtm ACK [c819a83](bitcoin/bitcoin@c819a83). can you update the PR description?
  glozow:
    lgtm ACK c819a83. can you update the PR description?

Tree-SHA512: 0972e0a05934e1b014fdeca0c235065aa017ba9abf74b3018f514e4d8022ef02b7f042a07d3675144b51449492468aea6b5b0183233ad7f1bab887d18e3d06af

Author: glozow

src/kernel/mempool_persist.cpp

@@ -205,7 +205,7 @@ bool DumpMempool(const CTxMemPool& pool, const fs::path& dump_path, FopenFn mock
         }
         auto last = SteadyClock::now();
 
-        LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n",
+        LogPrintf("Dumped mempool: %.3fs to copy, %.3fs to dump\n",
                   Ticks<SecondsDouble>(mid - start),
                   Ticks<SecondsDouble>(last - mid));
     } catch (const std::exception& e) {

src/policy/fees.cpp

@@ -1055,7 +1055,7 @@ void CBlockPolicyEstimator::FlushUnconfirmed()
         _removeTx(mi->first, false); // this calls erase() on mapMemPoolTxs
     }
     const auto endclear{SteadyClock::now()};
-    LogPrint(BCLog::ESTIMATEFEE, "Recorded %u unconfirmed txs from mempool in %gs\n", num_entries, Ticks<SecondsDouble>(endclear - startclear));
+    LogPrint(BCLog::ESTIMATEFEE, "Recorded %u unconfirmed txs from mempool in %.3fs\n", num_entries, Ticks<SecondsDouble>(endclear - startclear));
 }
 
 std::chrono::hours CBlockPolicyEstimator::GetFeeEstimatorFileAge()