Add InitError(error, details) overload

This is only used in the current PR to avoid ugly
`strprintf(Untranslated("%s:\n%s"), str, MakeUnorderedList(details)`
boilerplate in init code. But in the future the function could be extended and
more widely used to include more details in GUI error messages or display them
in a more readable way, see code comment.

src/node/interface_ui.cpp

@@ -4,6 +4,7 @@
 
 #include <node/interface_ui.h>
 
+#include <util/string.h>
 #include <util/translation.h>
 
 #include <boost/signals2/optional_last_value.hpp>
@@ -62,6 +63,18 @@ bool InitError(const bilingual_str& str)
     return false;
 }
 
+bool InitError(const bilingual_str& str, const std::vector<std::string>& details)
+{
+    // For now just flatten the list of error details into a string to pass to
+    // the base InitError overload. In the future, if more init code provides
+    // error details, the details could be passed separately from the main
+    // message for rich display in the GUI. But currently the only init
+    // functions which provide error details are ones that run during early init
+    // before the GUI uiInterface is registered, so there's no point passing
+    // main messages and details separately to uiInterface yet.
+    return InitError(details.empty() ? str : strprintf(Untranslated("%s:\n%s"), str, MakeUnorderedList(details)));
+}
+
 void InitWarning(const bilingual_str& str)
 {
     uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_WARNING);