ci: Use stable Rust for docs, remove unstable features

- Switch from nightly to stable toolchain
- Remove --enable-index-page -Zunstable-options (caused template error)
- Remove --document-private-items for cleaner public API docs

Author: ApiliumTeam

.github/workflows/docs.yml

@@ -24,8 +24,8 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - name: Install Rust (nightly for docs features)
-        uses: dtolnay/rust-toolchain@nightly
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
 
       - name: Install system dependencies
         run: |
@@ -39,15 +39,13 @@ jobs:
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ runner.os }}-cargo-docs-nightly-${{ hashFiles('**/Cargo.lock') }}
+          key: ${{ runner.os }}-cargo-docs-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: |
-            ${{ runner.os }}-cargo-docs-nightly-
+            ${{ runner.os }}-cargo-docs-
 
       - name: Build rustdoc
         run: |
-          cargo doc -p aingle_minimal --no-deps --document-private-items
-        env:
-          RUSTDOCFLAGS: --enable-index-page -Zunstable-options
+          cargo doc -p aingle_minimal --no-deps
 
       - name: Create index redirect
         run: |