format before comparing shader build diff in workflows

Author: schell

.github/workflows/push.yaml

@@ -84,6 +84,7 @@ jobs:
       - run: cargo shaders
       - run: cargo linkage
       - run: cargo build -p renderling
+      - run: cargo +nightly fmt
       - run: git diff --exit-code --no-ext-diff
 
   # BAU clippy lints