Add command to reformat description

Avoid description to take multiple lines.

Guides/ics-vim.md

@@ -6,6 +6,10 @@ Tips to modify an autogenerated ics file with the Vim text editor.
 
 `%s/\/\?\(INGE_\)\?EI_[A-Z0-9_]*,\? \/\? \?//g`
 
+## Reformat description
+
+`%s/\n - DESCRIPTION : \(.*\)$/\1/`
+
 ## Remove useless description
 
 Vim command : `:%s/^ - DESCRIPTION : \n//`