Remove some out-of-date comments.

These should have been removed in #330.

Author: nnethercote

.github/workflows/ci_linux.yml

@@ -163,7 +163,6 @@ jobs:
               --exclude cust
           '
 
-      # Exclude cust_raw because it triggers hundreds of warnings.
       - name: Check documentation
         run: |
           docker exec "$CONTAINER_NAME" bash -lc 'set -euo pipefail

.github/workflows/ci_windows.yml

@@ -106,7 +106,6 @@ jobs:
         run: cargo test --workspace --exclude blastoff --exclude cudnn --exclude cudnn-sys --exclude cust
 
       # Exclude crates that require cuDNN, not available on Windows CI: cudnn, cudnn-sys.
-      # Exclude cust_raw because it triggers hundreds of warnings.
       - name: Check documentation
         env:
           RUSTDOCFLAGS: -Dwarnings