docs: use doxygen-awesome-css (#2758)

.github/workflows/CI.yml

@@ -992,7 +992,6 @@ jobs:
           pacman -U --noconfirm mingw-w64-ucrt-x86_64-curl-8.8.0-1-any.pkg.tar.zst
           pacman -Syu --noconfirm \
             --ignore=mingw-w64-ucrt-x86_64-curl \
-            doxygen \
             git \
             mingw-w64-ucrt-x86_64-boost \
             mingw-w64-ucrt-x86_64-cmake \
@@ -1007,6 +1006,31 @@ jobs:
             mingw-w64-ucrt-x86_64-opus \
             mingw-w64-ucrt-x86_64-toolchain
 
+      - name: Install Doxygen
+        # GCC compiled doxygen has issues when running graphviz
+        env:
+          DOXYGEN_VERSION: "1.11.0"
+        run: |
+          # Set version variables
+          $doxy_ver = $env:DOXYGEN_VERSION
+          $_doxy_ver = $doxy_ver.Replace(".", "_")
+
+          # Download the Doxygen installer
+          Invoke-WebRequest -Uri `
+            "https://github.com/doxygen/doxygen/releases/download/Release_${_doxy_ver}/doxygen-${doxy_ver}-setup.exe" `
+            -OutFile "doxygen-setup.exe"
+
+          # Run the installer
+          Start-Process `
+            -FilePath .\doxygen-setup.exe `
+            -ArgumentList `
+              '/VERYSILENT' `
+          -Wait `
+          -NoNewWindow
+
+          # Clean up
+          Remove-Item -Path doxygen-setup.exe
+
       - name: Setup python
         # use this instead of msys2 python due to known issues using wheels, https://www.msys2.org/docs/python/
         id: setup-python