chore: delete external resources from tolk overview (#1627)

Author: it09

languages/tolk/overview.mdx

@@ -89,11 +89,3 @@ Recommended starting points:
 - [Idioms and conventions](/languages/tolk/idioms-conventions)
 - [Type system](/languages/tolk/types/list-of-types)
 - [Message handling](/languages/tolk/features/message-handling)
-
-## External resources
-
-Useful links outside this documentation:
-
-- [TON Dev chats](https://t.me/addlist/1r5Vcb8eljk5Yzcy) in Telegram
-- [@tolk\_lang channel](https://t.me/tolk_lang) in Telegram
-- [GitHub](https://github.com/ton-blockchain/ton) for issues and sources