doc: Add 'vulkan' package to Windows vcpkg install instructions.

Author: heinezen

doc/build_instructions/windows_msvc.md

@@ -47,7 +47,11 @@ _Note:_ Also ensure that `python` and `python3` both point to the correct and th
 
     vcpkg install dirent eigen3 fontconfig freetype harfbuzz libepoxy libogg libpng opus opusfile qtbase qtdeclarative qtmultimedia toml11
 
- _Note:_ The `qt6` port in vcpkg has been split into multiple packages, build times are acceptable now.
+If you also want Vulkan graphics support, you should also run this command:
+
+    vcpkg install vulkan
+
+ _Note:_ The `qt` port in vcpkg has been split into multiple packages, build times are acceptable now.
  If you want, you can still use [the prebuilt version](https://www.qt.io/download-open-source/) instead.
  If you do so, include `-DCMAKE_PREFIX_PATH=<QT6 directory>` in the cmake configure command.