Bug 1467: Allow tabs instead of spaces in extension file

https://winscp.net/tracker/1467
(cherry picked from commit 982164f03c4110e0207e3d1eff0b6d76c1713c2e)

Source commit: fb4ca8b4336b16cdab574f2d5b9baa93d64b794c

source/windows/WinConfiguration.cpp

@@ -2746,6 +2746,8 @@ 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))
       {