Update icons in rust

Updated icons
- Diagnostic states
- Sidebar icons (project, contacts)
- Navigation arrows

crates/zed/src/zed.rs

@@ -244,7 +244,7 @@ pub fn initialize_workspace(
 
     workspace.left_sidebar().update(cx, |sidebar, cx| {
         sidebar.add_item(
-            "icons/folder-tree-solid-14.svg",
+            "icons/Icon16FolderTree.svg",
             "Project Panel".to_string(),
             project_panel.into(),
             cx,
@@ -252,7 +252,7 @@ pub fn initialize_workspace(
     });
     workspace.right_sidebar().update(cx, |sidebar, cx| {
         sidebar.add_item(
-            "icons/contacts-solid-14.svg",
+            "icons/Icon16UserGroup.svg",
             "Contacts Panel".to_string(),
             contact_panel.into(),
             cx,