add rustfmt

This reverts commit 81158ca818.

.gitea/workflows/checks.yml

@@ -0,0 +1,16 @@
+name: checks
+on:
+  - push
+  - pull_request
+
+jobs:
+  lint:
+    runs_on: "alpine_amd64"
+    container:
+      image: "rust:1.73-alpine3.18"
+    name: format
+    steps:
+      - name: TODO put in image base
+        run: rustup component add rustfmt
+      - name: rustfmt
+        run: cargo fmt --check