Add auto-completion support for snippet files (#23698)

Release Notes:

- Added auto-completion support for snippet files.


![image](https://github.com/user-attachments/assets/ad165fc7-a6e7-426c-8892-f7004515dfc7)

crates/languages/Cargo.toml

@@ -60,6 +60,7 @@ serde.workspace = true
 serde_json.workspace = true
 settings.workspace = true
 smol.workspace = true
+snippet_provider.workspace = true
 task.workspace = true
 toml.workspace = true
 tree-sitter = { workspace = true, optional = true }