Removed extra blank space after title (#1387)

The blank space did not allow the frontmatter to be displayed correctly

Author: ambaradan

docs/guides/desktop/xfce_installation.md

@@ -1,5 +1,5 @@
 ---
-title: XFCE Desktop 
+title: XFCE Desktop
 author: Gerard Arthus, Steven Spencer
 contributors: Steven Spencer, Antoine Le Morvan, K.Prasad
 tested_with: 8.5, 8.6, 9.0