Fix missing images and Arabic fonts in course PDFs (#2544)

Let's give #2531 another try
- Fixes missing images in PDFs (those specified as <img> elements)
- Configures Arabic fonts

[The
fix](https://github.com/max-heller/mdbook-pandoc/pull/144/files#diff-b17b0f99aa22ee1ccf99778ca74c3c7a27af87f41544194cc95f82c012e8a507)
for the Persian translation issue, if you're curious.

.github/workflows/install-mdbook/action.yml

@@ -17,11 +17,11 @@ runs:
 
     - name: Install mdbook-pandoc and related dependencies
       run: |
-        cargo install mdbook-pandoc --locked --version 0.7.0
+        cargo install mdbook-pandoc --locked --version 0.9.0
         sudo apt-get update
-        sudo apt-get install -y texlive texlive-luatex texlive-lang-cjk librsvg2-bin fonts-noto
-        curl -LsSf https://github.com/jgm/pandoc/releases/download/3.2.1/pandoc-3.2.1-linux-amd64.tar.gz | tar zxf -
-        echo "$PWD/pandoc-3.2.1/bin" >> $GITHUB_PATH
+        sudo apt-get install -y texlive texlive-luatex texlive-lang-cjk texlive-lang-arabic librsvg2-bin fonts-noto
+        curl -LsSf https://github.com/jgm/pandoc/releases/download/3.6.2/pandoc-3.6.2-linux-amd64.tar.gz | tar zxf -
+        echo "$PWD/pandoc-3.6.2/bin" >> $GITHUB_PATH
       shell: bash
 
     - name: Install mdbook-i18n-helpers

book.toml

@@ -40,11 +40,18 @@ pdf-engine = "lualatex"
 mainfont = "Noto Serif"
 sansfont = "Noto Sans"
 monofont = "Noto Sans Mono"
-mainfontfallback = ["NotoColorEmoji:mode=harf"]
+mainfontfallback = [
+  "NotoColorEmoji:mode=harf",
+  "NotoNaskhArabic:",
+]
+sansfontfallback = [
+  "NotoSansArabic:",
+]
 monofontfallback = [
   "NotoColorEmoji:mode=harf",
   "NotoSansMath:",
   "NotoSansMonoCJKSC:",
+  "NotoSansArabic:",
 ]
 geometry = ["margin=1.25in"]
 linkcolor = "blue"