Add EditorConfig rules, fix trailing whitespaces

.editorconfig

@@ -0,0 +1,22 @@
+# EditorConfig configuration for Colmena
+
+# Top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file, utf-8 charset
+[*]
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+charset = utf-8
+
+# Rust
+[*.rs]
+indent_style = space
+indent_size = 2
+
+# Vendored
+[manual/theme/highlight.js]
+end_of_line = unset
+insert_final_newline = unset
+trim_trailing_whitespace = unset

.github/workflows/editorconfig.yml

@@ -0,0 +1,20 @@
+name: Check EditorConfig
+
+on:
+  pull_request:
+  push:
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2.3.4
+      - uses: cachix/install-nix-action@v15
+
+      - name: Enable binary cache (optional)
+        uses: cachix/cachix-action@v10
+        with:
+          name: colmena
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - run: nix-shell --run "editorconfig-checker"

flake.nix

@@ -52,7 +52,7 @@
 
     devShell = pkgs.mkShell {
       inputsFrom = [ defaultPackage ];
-      packages = with pkgs; [ clippy mdbook python3 rust-analyzer ];
+      packages = with pkgs; [ clippy mdbook python3 editorconfig-checker rust-analyzer ];
       shellHook = ''
         export NIX_PATH=nixpkgs=${pkgs.path}
       '';