update comments

Author: tgross35

.github/workflows/main.yaml

@@ -119,10 +119,10 @@ jobs:
     - name: Print runner information
       run: uname -a
 
-    # Native runners don't have rustup by default
+    # Native ppc and s390x runners don't have rustup by default
     - name: Install rustup
       if: matrix.os == 'ubuntu-24.04-ppc64le' || matrix.os == 'ubuntu-24.04-s390x'
-      run: sudo apt-get install -y rustup
+      run: sudo apt-get update && sudo apt-get install -y rustup
 
     - uses: actions/checkout@v4
     - name: Install Rust (rustup)
@@ -135,7 +135,7 @@ jobs:
         rustup default "$channel"
         rustup target add "${{ matrix.target }}"
 
-    # Our scripts use nextest if possible. This is skipped on  the native ppc
+    # Our scripts use nextest if possible. This is skipped on the native ppc
     # and s390x runners since install-action doesn't support them.
     - uses: taiki-e/install-action@nextest
       if: "!(matrix.os == 'ubuntu-24.04-ppc64le' || matrix.os == 'ubuntu-24.04-s390x')"