Turn Clippy checks back on.

.github/workflows/build-one.yml

@@ -79,14 +79,10 @@ jobs:
               target/release/humility -a target/${{ inputs.app_name }}/dist/build-${{ inputs.app_name }}-image-$image.zip manifest; \
           done
 
-      # TODO: Clippy temporarily disabled 2024-04 while people clean up
-      # the new Clippy warnings resulting from the last toolchain
-      # upgrade. If you're reading this, try turning it back on and see
-      # if we're good yet.
-      #- name: Clippy
-      #  if: inputs.os == 'ubuntu-latest'
-      #  run: |
-      #    cargo xtask clippy ${{ inputs.app_toml}} -- --deny warnings
+      - name: Clippy
+        if: inputs.os == 'ubuntu-latest'
+        run: |
+          cargo xtask clippy ${{ inputs.app_toml}} -- --deny warnings
 
       # upload the output of our build
       - name: Upload build archive