chore: add mermaid

.github/workflows/github_pages.yml

@@ -32,17 +32,13 @@ jobs:
           key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
       - name: Check and install mdbook if not already installed
         run: |
-          if ! cargo install --list | grep -q "mdbook v"; then
+          if ! command -v mdbook &> /dev/null; then
             cargo install mdbook
-          else
-            echo "mdbook is already installed"
           fi
       - name: Check and install mdbook-mermaid if not already installed
         run: |
-          if ! cargo install --list | grep -q "mdbook-mermaid v"; then
+          if ! command -v mdbook-mermaid &> /dev/null; then
             cargo install mdbook-mermaid
-          else
-            echo "mdbook-mermaid is already installed"
           fi
       - name: build book
         run: make build