markdown preview: Improve live preview (#10205)

This PR contains various improvements for the markdown preview (some of
which were originally part of #7601).
Some improvements can be seen in the video (see also release notes down
below):


https://github.com/zed-industries/zed/assets/53836821/93324ee8-d366-464a-9728-981eddbfdaf7

Release Notes:
- Added action to open markdown preview in the same pane
- Added support for displaying channel notes in markdown preview
- Added support for displaying the current active editor when opening
markdown preview
- Added support for scrolling the editor to the corresponding block when
double clicking an element in markdown preview
- Improved pane creation handling when opening markdown preview
- Fixed markdown preview displaying non-markdown files

crates/auto_update/src/auto_update.rs

@@ -11,7 +11,7 @@ use gpui::{
 };
 use isahc::AsyncBody;
 
-use markdown_preview::markdown_preview_view::MarkdownPreviewView;
+use markdown_preview::markdown_preview_view::{MarkdownPreviewMode, MarkdownPreviewView};
 use schemars::JsonSchema;
 use serde::Deserialize;
 use serde_derive::Serialize;
@@ -238,10 +238,11 @@ fn view_release_notes_locally(workspace: &mut Workspace, cx: &mut ViewContext<Wo
                                 .new_view(|cx| Editor::for_multibuffer(buffer, Some(project), cx));
                             let workspace_handle = workspace.weak_handle();
                             let view: View<MarkdownPreviewView> = MarkdownPreviewView::new(
+                                MarkdownPreviewMode::Default,
                                 editor,
                                 workspace_handle,
-                                Some(tab_description),
                                 language_registry,
+                                Some(tab_description),
                                 cx,
                             );
                             workspace.add_item_to_active_pane(Box::new(view.clone()), cx);