docs: update Documentation about export-filename

Author: xmatthias

docs/advanced-backtesting.md

@@ -55,7 +55,7 @@ output file. This allows you to keep historical versions of backtest results and
 them at a later date:
 
 ``` bash
-freqtrade backtesting -c <config.json> --timeframe <tf> --strategy <strategy_name> --timerange=<timerange> --export=signals --export-filename=/tmp/mystrat_backtest.json
+freqtrade backtesting-analysis -c <config.json> --timeframe <tf> --strategy <strategy_name> --timerange=<timerange> --export=signals --export-filename=user_data/backtest-results/backtest-result-2025-03-05_20-38-34.zip
 ```
 
 You should see some output similar to below in the logs with the name of the timestamped

docs/backtesting.md

@@ -105,12 +105,14 @@ Only use this if you're sure you'll not want to plot or analyze your results fur
 
 ---
 
-Exporting trades to file specifying a custom filename
+Exporting trades to file specifying a custom directory
 
 ```bash
-freqtrade backtesting --strategy backtesting --export trades --export-filename=backtest_samplestrategy.json
+freqtrade backtesting --strategy backtesting --export trades --export-filename=user_data/custom-backtest-results
 ```
 
+---
+
 Please also read about the [strategy startup period](strategy-customization.md#strategy-startup-period).
 
 ---