Enable the custom feature for rustdoc job

Author: newpavlov

.github/workflows/workspace.yml

@@ -78,4 +78,4 @@ jobs:
       - name: Generate Docs
         env:
           RUSTDOCFLAGS: "-Dwarnings --cfg docsrs"
-        run: cargo doc --no-deps
+        run: cargo doc --no-deps --features custom