Add language icons to the language selector (#21298)

Closes https://github.com/zed-industries/zed/issues/21290

This is a first attempt to show the language icons to the selector.
Ideally, I wouldn't like to have yet another place mapping extensions to
icons, as we already have the `file_types.json` file doing that, but I'm
not so sure how to pull from it yet. Maybe in a future pass we'll
improve this and make it more solid.

<img width="700" alt="Screenshot 2024-11-28 at 16 10 27"
src="https://github.com/user-attachments/assets/683c3bef-5389-470f-a41e-3d510b927b61">

Release Notes:

- N/A

---------

Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

assets/icons/file_icons/diff.svg

@@ -0,0 +1,5 @@
+<svg width="17" height="16" viewBox="0 0 17 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M8.5 3L8.5 10" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M5 6.5H12" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M5 13H12" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

assets/icons/file_icons/file_types.json

@@ -34,6 +34,7 @@
     "dat": "storage",
     "db": "storage",
     "dbf": "storage",
+    "diff": "diff",
     "dll": "storage",
     "doc": "document",
     "docx": "document",
@@ -112,6 +113,7 @@
     "mkv": "video",
     "ml": "ocaml",
     "mli": "ocaml",
+    "mod": "go",
     "mov": "video",
     "mp3": "audio",
     "mp4": "video",
@@ -185,6 +187,7 @@
     "wmv": "video",
     "woff": "font",
     "woff2": "font",
+    "work": "go",
     "wv": "audio",
     "xls": "document",
     "xlsx": "document",
@@ -239,6 +242,9 @@
     "default": {
       "icon": "icons/file_icons/file.svg"
     },
+    "diff": {
+      "icon": "icons/file_icons/diff.svg"
+    },
     "docker": {
       "icon": "icons/file_icons/docker.svg"
     },