Fix scrolling and wrapping in the markdown preview renderer (#7234)

Release Notes:

- N/A

crates/markdown_preview/src/markdown_preview_view.rs

@@ -114,13 +114,16 @@ impl Render for MarkdownPreviewView {
             .key_context("MarkdownPreview")
             .track_focus(&self.focus_handle)
             .id("MarkdownPreview")
-            .overflow_scroll()
+            .overflow_y_scroll()
+            .overflow_x_hidden()
             .size_full()
             .bg(cx.theme().colors().editor_background)
             .p_4()
             .children(render_markdown(&self.contents, &self.languages, cx));
 
         div().flex_1().child(
+            // FIXME: This shouldn't be necessary
+            // but the overflow_scroll above doesn't seem to work without it
             canvas(move |bounds, cx| {
                 rendered_markdown.into_any().draw(
                     bounds.origin,

crates/markdown_preview/src/markdown_renderer.rs

@@ -174,7 +174,7 @@ where
                 }
 
                 let element = self.render_md_from_range(source_range.clone(), cx);
-                let paragraph = h_flex().mb_3().child(element);
+                let paragraph = div().mb_3().child(element);
 
                 self.finished.push(paragraph);
             }