Add Vale GitHub workflow (#1196)

* Add Vale config file

* Add GH workflow

* Add SUSE style guide rules

* Add reference of SUSE style guide and Vale to README

Co-authored-by: Billy Tat <btat@suse.com>

---------

Co-authored-by: Billy Tat <btat@suse.com>

.github/workflows/vale.yml

@@ -0,0 +1,53 @@
+# This action gets all changed markdown files in /docs and /versioned_docs using tj-actions/changed-files@v42
+# It compares new commits in the PR with the base commit (github.event.pull_request.base.sha)
+# It checks if no markdown files are changed 
+# It shows a count of markdown files and lists all changed markdown files
+# It uses Vale (https://vale.sh/docs/vale-cli/installation/) to provide feedback base off the SUSE Style Guide / OpenSUSE style rules (https://github.com/openSUSE/suse-vale-styleguide)
+
+name: Style check
+on: [pull_request]
+
+jobs:
+  vale-lint:
+    name: runner / vale
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # OR "2" -> To retrieve the preceding commit.
+          submodules: true
+      - name: Get all changed markdown files
+        id: changed-markdown-files
+        uses: tj-actions/changed-files@v42
+        with:
+            # Avoid using single or double quotes for multiline patterns
+            files: |
+               docs/**
+               versioned_docs/**
+            separator: ","
+            base_sha: ${{ github.event.pull_request.base.sha }}
+        env:
+            ALL_CHANGED_FILES: ${{ 0 }}
+      - name: No files changed?
+        if: steps.changed-markdown-files.outputs.any_changed == 'false'
+        run: |
+              echo "No files changed"
+              echo "ALL_CHANGED_FILES=$ALL_CHANGED_FILES" >> $GITHUB_ENV
+      - name: List all changed files markdown files
+        if: steps.changed-markdown-files.outputs.any_changed == 'true'
+        env:
+            ALL_CHANGED_FILES: ${{ steps.changed-markdown-files.outputs.all_changed_files }}
+            ALL_CHANGED_FILES_COUNT: ${{ steps.changed-markdown-files.outputs.all_changed_files_count }}
+            SHA: ${{ github.head_ref }}
+            HEAD: ${{ github.base_ref }}
+        run: |
+            echo "Total Files Changed:" ${ALL_CHANGED_FILES_COUNT}
+            echo ${ALL_CHANGED_FILES}
+            echo "ALL_CHANGED_FILES=$ALL_CHANGED_FILES" >> $GITHUB_ENV
+      - uses: errata-ai/vale-action@v2.1.0
+        if: steps.changed-markdown-files.outputs.any_changed == 'true'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          separator: ", "
+          files: ${{ env.ALL_CHANGED_FILES }}

.gitmodules

@@ -0,0 +1,3 @@
+[submodule ".github/styles/suse-vale-styleguide"]
+	path = .github/styles/suse-vale-styleguide
+	url = https://github.com/openSUSE/suse-vale-styleguide

.vale.ini

@@ -0,0 +1,7 @@
+StylesPath = .github/styles
+
+[formtats]
+mdx = md
+
+[*.md]
+BasedOnStyles = suse-vale-styleguide

README.md

@@ -27,7 +27,17 @@ The file paths in the repo correspond to the URLs for pages on the docs website.
 
 ### Style & Formatting
 
-The docs are written in [Markdown](https://www.markdownguide.org/getting-started/). We refer to the Microsoft [style guide](https://learn.microsoft.com/en-us/style-guide/welcome/) and use standard American English. Many pages are also available in Simplified Chinese.
+The docs are written in [Markdown](https://www.markdownguide.org/getting-started/). We use standard American English and many pages are also available in Simplified Chinese.
+
+Moving forward, we are referring to the SUSE [style guide](https://documentation.suse.com/style/current/pdf/style-guide_en.pdf). The **Style check / runner / vale (pull_request)** check used [Vale](https://vale.sh/) to make style and grammar suggestions for new or updated documentation based on the SUSE style guide. To review these suggestions when working on a PR:
+
+1. Select the details of the **Style check / runner / vale (pull_request)** check.
+1. In the logs, go to **Run errata-ai/vale-action@v2.1.0** and select **Running vale with reviewdog 🐶 ...** to view the suggestions.
+1. New or updated files are checked against the SUSE style guide. Suggestions have the following format: '{"message": "[suse-vale-styleguide.Rule] Rule description", "location": {"path": "file-path", "range": {"start": {"line": , "column": }}}, "severity": " "}'
+
+    For example: '{"message": "[suse-vale-styleguide.Usage] Use 'certain' instead of 'some'", "location": {"path": "docs/contribute-to-rancher.md", "range": {"start": {"line": 3, "column": 132}}}, "severity": "WARNING"}'
+
+1. Incorporate the suggestions when possible and appropriate.
 
 Every docs page contain metadata in the first few lines: