Clarify Installation Instructions for Windows

[ParticleBert]

Issue description

Maybe I am a little bit too detailed here, but the installation instructions tell me to

Download a release version and copy the included MarkdownViewerPlusPlus.dll to the plugins sub-folder at your Notepad++ installation directory.

This doesn't work. If I place the File MarkdownViewerPlusPlus.dll in the plugins-folder, Notepad++ won't recognize the plugin. A better phrase to describe the installation would be

Download a release version and unzip the directory into the plugins-Folder of your Notepad++ installation directory.

[manciuszz]

The last update was done 2 years ago. If its not working, its most probably because its broken on the latest notepad versions. Try https://github.com/mohzy83/NppMarkdownPanel I'm using it on Notepad++ 7.6.6 with no issues.

[ParticleBert]

Thanks.