Add reviewdog/languagetool

Author: kazk

.github/workflows/reviewdog.yml

@@ -13,3 +13,16 @@ jobs:
           locale: "US"
           # Check all files
           filter_mode: nofilter
+
+  languagetool:
+    name: runner / languagetool
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: reviewdog/action-languagetool@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          reporter: github-pr-review
+          level: warning
+          language: en-US
+          patterns: "**/*.md **/*.mdx **/*.txt glossary.yml"