Update shard.yml to include target (#5608)

[shard.yml]
- Include a target for LSPs to use as an entrypoint:
  (https://github.com/elbywan/crystalline?tab=readme-ov-file#entry-point)

shard.yml

@@ -5,6 +5,10 @@ authors:
   - Invidious team <contact@invidious.io>
   - Contributors!
 
+targets:
+  invidious:
+    main: src/invidious.cr
+
 description: |
    Invidious is an alternative front-end to YouTube