ci: add markdownlint, misspell and languagetool

JIRA: CI-94

.github/workflows/lint.yml

@@ -0,0 +1,41 @@
+# vim:sw=2:ts=2
+# static linters which can be run in a single repo (do not need phoenix-rtos-project)
+name: lint
+
+# on events
+on:
+  pull_request:
+    branches:
+      - master
+      - 'feature/*'
+
+jobs:
+  markdownlint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: reviewdog/action-markdownlint@v0
+        with:
+          github_token: ${{ secrets.github_token }}
+          reporter: github-pr-review
+          fail_on_error: true
+
+  misspell:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: reviewdog/action-misspell@v1
+        with:
+          github_token: ${{ secrets.github_token }}
+          reporter: github-pr-review
+          fail_on_error: true
+
+
+  languagetool:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: reviewdog/action-languagetool@v1
+        with:
+          github_token: ${{ secrets.github_token }}
+          reporter: github-pr-review

.markdownlint.yaml

@@ -0,0 +1,36 @@
+# Example markdownlint configuration with all properties set to their default value
+
+# Default state for all rules
+default: true
+
+# Path to configuration file to extend
+extends: null
+
+# MD010/no-hard-tabs - Hard tabs
+MD010:
+  # Include code blocks
+  code_blocks: false
+  # Fenced code languages to ignore
+  ignore_code_languages: []
+  # Number of spaces for each hard tab
+  spaces_per_tab: 4
+
+# MD013/line-length - Line length
+MD013:
+  # Number of characters
+  line_length: 120
+  # Number of characters for headings
+  heading_line_length: 120
+  # Number of characters for code blocks
+  code_block_line_length: 120
+  # Include code blocks
+  code_blocks: false
+  # Strict length checking
+  strict: false
+  # Stern length checking
+  stern: true
+
+# MD033/no-inline-html - Inline HTML
+MD033:
+  # Allowed elements
+  allowed_elements: [img]