Extend checking to the Introduction section

Author: spier

.github/workflows/vale.yml

@@ -20,7 +20,7 @@ jobs:
     - name: Vale Linting
       uses: errata-ai/vale-action@reviewdog
       with:
-        files: '["project-leader/"]'
+        files: '["introduction/", "project-leader/"]'
         vale_flags: "--glob=*.asciidoc"
         filter_mode: file
         debug: true

.gitignore

@@ -5,4 +5,4 @@ scripts/learningpath
 scripts/newsite
 scripts/.env
 .vs
-.github/vale/*
+.github/vale/*