Ensure that CI fails if extracted strings don't match (#2078)

- Ensures extracted strings get formatted before checking against index
- Fixes index check by switching from `git diff-index` to `git diff`,
and ensures the proper `--exit-code` flag is present (implicitly turned
on by `--quiet`)
- Adds actionable error message when the check fails
- Updates Github's actions versions from v3 to v4 (major version bump is
primarily just for default node version updates, but this way we'll get
future updates)
- Adds formatting step to npm script for extracting messages
- Runs a string extraction & format against current main

.github/workflows/frontend-build-check.yaml

@@ -12,15 +12,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Setup Node
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version: '18'
           cache: 'yarn'
           cache-dependency-path: frontend/yarn.lock
       - name: Restore cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: frontend/dist
           key: ${{ runner.os }}-btrix-frontend-build-${{ hashFiles('frontend/dist') }}
@@ -44,7 +44,7 @@ jobs:
         run: yarn test
       - name: Check extracted strings
         working-directory: frontend
-        run: yarn localize:extract && git diff-index HEAD --
+        run: yarn localize:extract && if ! git diff --quiet -- ; then echo "Error extracting strings, please run \`yarn localize:extract\` from the \`frontend\` directory and commit the results."; false; fi
       - name: Localization build
         working-directory: frontend
         run: yarn localize:build

frontend/package.json

@@ -96,7 +96,7 @@
     "lint:lit-analyzer": "lit-analyzer",
     "format": "prettier --write .",
     "format:check": "prettier --check .",
-    "localize:extract": "lit-localize extract",
+    "localize:extract": "lit-localize extract && prettier --write xliff/*.xlf",
     "localize:build": "lit-localize build"
   },
   "devDependencies": {
@@ -123,7 +123,7 @@
     "chromium": "^3.0.3"
   },
   "lint-staged": {
-    "*.{ts,js,html,css,json,webmanifest,xlf}": "prettier --write"
+    "*.{ts,js,html,css,json,webmanifest}": "prettier --write"
   },
   "husky": {
     "hooks": {