try to fix mdbook build

Author: wiz0u

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Install mdbook and cargo-binstall binaries
       uses: taiki-e/install-action@v2
       with:
-        tool: mdbook@0.5.1, cargo-binstall
+        tool: mdbook, cargo-binstall
     - name: Install mdbook extensions
       run: cargo binstall -y mdbook-mermaid mdbook-alerts mdbook-toc
 

book.toml

@@ -8,13 +8,12 @@ language = "en"
 git-repository-url = "https://github.com/TelegramBots/book"
 site-url = "/book/"
 additional-css = ["theme/custom.css"]
+admonitions = true
 
 [output.html.fold]
 enable = true
 level = 1
 
-[preprocessor.alerts]
-
 [preprocessor.toc]
 command = "mdbook-toc"
 renderer = ["html"]