infra: remove developer-tools cross-link from references index

Author: marc0olo

docs/references/index.md

@@ -7,10 +7,6 @@ sidebar:
 
 Technical reference material for ICP development. These pages cover exact specifications, canister IDs, costs, and error codes.
 
-## Tools
-
-- **[Developer Tools](../developer-tools/index.md)**: icp-cli, CDKs, JS SDK, PocketIC, ICP Ninja, and other toolchain components.
-
 ## Canisters
 
 - **[Management Canister](management-canister.md)**: API reference for the IC management canister (`aaaaa-aa`): canister lifecycle, signing, randomness, and more.