Add command to escape \n character

Guides/ics-vim.md

@@ -2,3 +2,16 @@
 
 Tips to modify an autogenerated ics file with the Vim text editor.
 
+## Remove unescaped \n
+
+Commande vim : `:%s/\\n//g`
+
+Before :
+```
+SUMMARY:TP - CCUBE - C000\n
+```
+
+After :
+```
+SUMMARY:TP - CCUBE - C000
+```