doc: mention all new packages also in the Getting Started guide.

doc/getting-started.dox

@@ -50,8 +50,10 @@ Magnum libraries support both separate compilation/installation and CMake
 subprojects. If you are lucky, you may already have Magnum packages ready for
 your platform and you can skip the rest of this section:
 
+-   @ref building-packages-hunter
 -   @ref building-packages-vcpkg
 -   @ref building-packages-arch
+-   @ref building-packages-msys
 -   @ref building-packages-deb
 -   @ref building-packages-gentoo
 -   @ref building-packages-brew