[gnome-builder] gui: remove gs_markdown parser

[Christian Hergert <chergert src gnome org>]

commit 3b7f39be7fca0421a0997526d6acb6acc76a4a04
Author: Tom A. Wagner <tom a wagner protonmail com>
Date:   Thu Jul 29 09:21:08 2021 +0200

    gui: remove gs_markdown parser
    
    The parser/renderer has been replaced by the new IdeMarkdownRenderer

 src/libide/gui/gs-markdown-private.h |  58 ---
 src/libide/gui/gs-markdown.c         | 873 -----------------------------------
 src/libide/gui/meson.build           |   2 -
 3 files changed, 933 deletions(-)
---
diff --git a/src/libide/gui/meson.build b/src/libide/gui/meson.build
index 42d24555f..5ebc9474f 100644
--- a/src/libide/gui/meson.build
+++ b/src/libide/gui/meson.build
@@ -58,7 +58,6 @@ install_headers(libide_gui_public_headers, subdir: libide_gui_header_subdir)
 #
 
 libide_gui_private_headers = [
-  'gs-markdown-private.h',
   'ide-application-private.h',
   'ide-environment-editor-row.h',
   'ide-frame-wrapper.h',
@@ -80,7 +79,6 @@ libide_gui_private_headers = [
 ]
 
 libide_gui_private_sources = [
-  'gs-markdown.c',
   'ide-application-actions.c',
   'ide-application-color.c',
   'ide-application-shortcuts.c',