markdown_preview: Remove unnecessary vec allocation (#44238)

Oleksii (Alexey) Orlenko created

Instead of allocating a one-element vec on the heap, we can just use an
array here (since `Editor::edit` accepts anything that implements
`IntoIterator`).

I haven't checked if there are more instances that can be simplified,
just accidentally stumbled upon this when working on something else in
the markdown preview crate.

Release Notes:

- N/A

Change summary

crates/markdown_preview/src/markdown_preview_view.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Detailed changes