[vte] sixel: Fix processing of DECSIXEL sequence when using UTF-8 C1 controls

[Christian Persch <chpe src gnome org>]

commit 5dd5823224558ffeb202c7969e03d5766fe3894e
Author: Christian Persch <chpe src gnome org>
Date:   Tue Dec 1 22:05:58 2020 +0100

    sixel: Fix processing of DECSIXEL sequence when using UTF-8 C1 controls
    
    The matching-controls check was getting the wrong introducer value.

 src/vteseq.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/vteseq.cc b/src/vteseq.cc
index 9826ce0f..5eab67c6 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -4457,7 +4457,7 @@ Terminal::DECSIXEL(vte::parser::Sequence const& seq)
                 if (!m_sixel_context)
                         m_sixel_context = std::make_unique<vte::sixel::Context>();
 
-                m_sixel_context->prepare(seq.st(),
+                m_sixel_context->prepare(seq.introducer(),
                                          fg.red >> 8, fg.green >> 8, fg.blue >> 8,
                                          bg.red >> 8, bg.green >> 8, bg.blue >> 8,
                                          back == VTE_DEFAULT_BG || transparent_bg,