feat: add magin_mode to show_config response

Author: xmatthias

freqtrade/rpc/api_server/api_schemas.py

@@ -229,6 +229,7 @@ class ShowConfig(BaseModel):
     api_version: float
     dry_run: bool
     trading_mode: str
+    margin_mode: str
     short_allowed: bool
     stake_currency: str
     stake_amount: str

freqtrade/rpc/rpc.py

@@ -136,6 +136,7 @@ def _rpc_show_config(
             "strategy_version": strategy_version,
             "dry_run": config["dry_run"],
             "trading_mode": config.get("trading_mode", "spot"),
+            "margin_mode": config.get("margin_mode", ""),
             "short_allowed": config.get("trading_mode", "spot") != "spot",
             "stake_currency": config["stake_currency"],
             "stake_currency_decimals": decimals_per_coin(config["stake_currency"]),