Fix f1144de: "knots" missing from settings units list. (#12082)

Knots were added as a setting but not included in the settings list so were saved as a number instead of string.

src/table/settings/locale_settings.ini

@@ -13,7 +13,7 @@ static void SettingsValueVelocityUnit(const IntSettingDesc &sd, uint first_param
 uint8_t _old_units;                                      ///< Old units from old savegames
 
 static constexpr std::initializer_list<const char*> _locale_currencies{"GBP", "USD", "EUR", "JPY", "ATS", "BEF", "CHF", "CZK", "DEM", "DKK", "ESP", "FIM", "FRF", "GRD", "HUF", "ISK", "ITL", "NLG", "NOK", "PLN", "RON", "RUR", "SIT", "SEK", "TRY", "SKK", "BRL", "EEK", "LTL", "KRW", "ZAR", "custom", "GEL", "IRR", "RUB", "MXN", "NTD", "CNY", "HKD", "INR", "IDR", "MYR", "LVL"};
-static constexpr std::initializer_list<const char*> _locale_units{"imperial", "metric", "si", "gameunits"};
+static constexpr std::initializer_list<const char*> _locale_units{"imperial", "metric", "si", "gameunits", "knots"};
 
 static_assert(_locale_currencies.size() == CURRENCY_END);