Fix link formatting in Installation.md

Updated link format for ffmpeg installation instructions.

Author: qwertygc

docs/doc/en/2.1.-Installation.md

@@ -9,7 +9,7 @@ path: 2.1.-Installation
 For the manual installations (using the command line or terminal) I mention a specific release version, for example version 3.7. Please check on the [releases page](https://github.com/ccbogel/QualCoder/releases) for the most current version, as it may be newer. 
 
 ### Prerequisites
-VLC is optional, but you will need it installed if you need to do any audio/video coding. Occasionally on some operating systems (e.g. Fedora) QualCoder cannot find VLC to use it. Optionally, install ffmpeg for waveform display, see https://phoenixnap.com/kb/ffmpeg-windows
+VLC is optional, but you will need it installed if you need to do any audio/video coding. Occasionally on some operating systems (e.g. Fedora) QualCoder cannot find VLC to use it. Optionally, install ffmpeg for waveform display, see [phoenixnap.com/kb/ffmpeg-windows](https://phoenixnap.com/kb/ffmpeg-windows).
 
 ### Windows