Bug 1467: Allow tabs instead of spaces in extension file

https://winscp.net/tracker/1467

Source commit: 5901a4fcf61a4ac27b102c1b3635f1185d8b60c0

source/windows/WinConfiguration.cpp

@@ -2733,6 +2733,8 @@ void __fastcall TCustomCommandType::LoadExtension(TStrings * Lines, const Unicod
     UnicodeString Line = Lines->Strings[Index].Trim();
     if (!Line.IsEmpty())
     {
+      Line = ReplaceChar(Line, L'\t', L' ');
+
       bool IsComment = false;
       if (StartsText(ExtensionMark, Line))
       {