gpui: Press enter, space to trigger click to focused element (#35075)

Release Notes:

- N/A

> Any user interaction that is equivalent to a click, such as pressing
the Space key or Enter key while the element is focused. Note that this
only applies to elements with a default key event handler, and
therefore, excludes other elements that have been made focusable by
setting the
[tabindex](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Global_attributes/tabindex)
attribute.

https://developer.mozilla.org/en-US/docs/Web/API/Element/click_event

---------

Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Umesh Yadav <23421535+imumesh18@users.noreply.github.com>

crates/markdown_preview/src/markdown_preview_view.rs

@@ -261,7 +261,7 @@ impl MarkdownPreviewView {
                                 .group("markdown-block")
                                 .on_click(cx.listener(
                                     move |this, event: &ClickEvent, window, cx| {
-                                        if event.down.click_count == 2 {
+                                        if event.click_count() == 2 {
                                             if let Some(source_range) = this
                                                 .contents
                                                 .as_ref()