build iOS in CI (#440)

- add an iOS build in CI to catch iOS-only build breaks
- move the docs build into the same macOS runner

Author: davidkoski

.github/workflows/pull_request.yml

@@ -69,17 +69,6 @@ jobs:
         run: |
           pre-commit run --all || (echo "Style checks failed, please install pre-commit and run pre-commit run --all and push the change"; echo ""; git --no-pager diff; exit 1)
 
-  docs:
-    needs: lint
-    if: github.repository == 'ml-explore/mlx-swift'
-    runs-on: [self-hosted, macos]
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          submodules: recursive
-
-      - name: Verify documentation
-        run: scripts/verify-docs.sh
 
   mac_build_and_test:
     needs: lint
@@ -99,6 +88,17 @@ jobs:
         run: |
           brew install cmake ninja
 
+      - name: Verify documentation
+        run: scripts/verify-docs.sh
+
+      - name: Build SwiftPM (Xcode, iOS)
+        shell: sh
+        run: |
+          xcodebuild -version
+          swift --version
+          rm -rf ~/Library/Developer/Xcode/DerivedData/*
+          xcodebuild build -scheme mlx-swift-Package -destination 'generic/platform=iOS'
+
       - name: Build SwiftPM (Xcode, macOS)
         shell: sh
         run: |