#2260 In Editor.cxx, Message::GetLastChild is broken for lParam=-1

[Zufu Liu]

The patch treats lParam <= 0 as no fold level set.

[Neil Hodgson]

There was a warning from gcc 9.2.0:

../src/Editor.h: In member function 'virtual Scintilla::sptr_t Scintilla::Internal::Editor::WndProc(Scintilla::Message, Scintilla::uptr_t, Scintilla::sptr_t)':
../src/Editor.h:631:11: warning: '<anonymous>' may be used uninitialized in this function [-Wmaybe-uninitialized]
  631 |   return {};
      |           ^

Its OK with return std::nullopt;

Committed as [dc965e] and [b7708a].

[Zufu Liu]

Updated patch to fix Document::GetLastChild().
value_or() is removed as it does do lazy evaluation.

[Neil Hodgson]

Committed GetLastChild as [9a4542].

Did OptionalColour show a warning? The warning from gcc in OptionalFoldLevel looks like a bug to me, possibly caused by incorrect inline handling or it being constexpr. std::nullopt is uglier and overly specific - {} is the generic empty thing.