Add Vale for content linting to the repo

.github/workflows/linting.yml

@@ -59,3 +59,17 @@ jobs:
           git add .
           pre-commit run --all-files --color always --verbose
         working-directory: cookie-template/python-template
+
+  lint-prose:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+
+      - name: Run Vale
+        uses: errata-ai/vale-action@d89dee975228ae261d22c15adcd03578634d429c # v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          filter_mode: nofilter
+          reporter: github-check

.gitignore

@@ -7,3 +7,11 @@
 python-template
 
 *.DS_Store
+
+# https://vale.sh/docs/keys/packages#vcs
+.github/styles/*
+!.github/styles/config/
+.github/styles/config/*
+!.github/styles/config/vocabularies/
+.github/styles/config/vocabularies/*
+!.github/styles/config/vocabularies/Base

.vale.ini

@@ -0,0 +1,24 @@
+StylesPath = .github/styles
+
+# https://github.com/errata-ai/packages
+Packages = proselint,\
+           write-good
+
+[*.md]
+BasedOnStyles = proselint,\
+                Vale,\
+                write-good
+
+# Disable
+Vale.Spelling = NO
+write-good.E-Prime = NO
+write-good.Passive = NO
+write-good.TooWordy = NO
+
+# `vale sync` in CI means the packages are then linted, so turn them off
+[.github/styles/**]
+BasedOnStyles =
+
+# Don't modify licence files
+[**/LICENSE*]
+BasedOnStyles =