docs: re-extract list-exchanges command partial

Author: xmatthias

docs/commands/list-exchanges.md

@@ -1,11 +1,16 @@
 ```
 usage: freqtrade list-exchanges [-h] [-v] [--no-color] [--logfile FILE] [-V]
                                 [-c PATH] [-d PATH] [--userdir PATH] [-1] [-a]
+                                [--trading-mode {spot,margin,futures}]
+                                [--dex-exchanges]
 
 options:
   -h, --help            show this help message and exit
   -1, --one-column      Print output in one column.
   -a, --all             Print all exchanges known to the ccxt library.
+  --trading-mode {spot,margin,futures}, --tradingmode {spot,margin,futures}
+                        Select Trading mode
+  --dex-exchanges       Print only DEX exchanges.
 
 Common arguments:
   -v, --verbose         Verbose mode (-vv for more, -vvv to get all messages).