fixes background reset (#2900)

* fixes background reset

* moves creation of default style out of loop

* patches with background_style

* removes commented code

helix-term/src/ui/editor.rs

@@ -668,8 +668,11 @@ impl EditorView {
         let hint = theme.get("hint");
 
         let mut lines = Vec::new();
+        let background_style = theme.get("ui.background");
         for diagnostic in diagnostics {
-            let style = Style::reset().patch(match diagnostic.severity {
+            let style = Style::reset()
+                .patch(background_style)
+                .patch(match diagnostic.severity {
                     Some(Severity::Error) => error,
                     Some(Severity::Warning) | None => warning,
                     Some(Severity::Info) => info,