Enable vale for prose linting (#3)

* Enable vale in CI

* Add vale config

* Tweak vale

* Update config

* Update .gitignore

* Switch back

* Rename CI

* Add badges

* Tidy up CI

* Change image

* Configure vale

* Delint

* Update README

.github/workflows/continuous_integration.yaml

@@ -0,0 +1,26 @@
+name: Continuous Integration
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  words:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Count words
+        run: make count
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Vale
+        uses: errata-ai/vale-action@reviewdog
+        with:
+          files: source/
+          fail_on_error: true