file_finder: Display file icons (#18091)

This PR adds file icons (like in tabs, the project panel and tab
switcher) to the file finder popup.

It's similar to [tab_switcher
icons](https://github.com/zed-industries/zed/pull/17115), but simpler,
because we're only dealing with actual files.

Release Notes:

- Added icons to the file finder.

Screenshot:

![image](https://github.com/user-attachments/assets/bd6a54c1-cdbd-415a-9a82-0cc7a0bb6ca2)

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

assets/settings/default.json

@@ -496,6 +496,11 @@
     // Whether a preview tab gets replaced when code navigation is used to navigate away from the tab.
     "enable_preview_from_code_navigation": false
   },
+  // Settings related to the file finder.
+  "file_finder": {
+    // Whether to show file icons in the file finder.
+    "file_icons": true
+  },
   // Whether or not to remove any trailing whitespace from lines of a buffer
   // before saving it.
   "remove_trailing_whitespace_on_save": true,