Update main.yml

Author: shenhuan2021

.github/workflows/main.yml

@@ -24,6 +24,10 @@ jobs:
       - name: Generate documentation tree in Markdown
         run: |
           tree doc -I 'node_modules|.git' -L 2 -o tree.md --charset ascii
+          
+      - name: Format tree.md for Markdown
+        run: |          
+          sed -i 's/^/    /' tree.md 
       
       - name: Merge Markdown files and insert tree
         run: |