Added missing colon (#292)

Made corrections after my previous commit.

source/applications/music_on_hold.md

@@ -3,10 +3,10 @@
 Music on hold can be in WAV or MP3 format.   
 You can adjust the volume of the MP3 audio from the 'Settings' tab. For best performance upload 16 bit, 8/16/32/48 kHz mono WAV files.   
 
-::{note}
+:::{note}
 
 To play an MP3 file you must have mod_shout enabled on the 'Modules' tab.   
-::
+:::
 
 ![image](../_static/images/applications/music_on_hold/fusionpbx_music_on_hold1.png)
 
@@ -42,10 +42,10 @@ To play an MP3 file you must have mod_shout enabled on the 'Modules' tab.
 
 ## Music on Hold Tips
 
-::{tip}   
+:::{tip}   
 
 When a new music on hold category mod_local_stream will be restarted. If it is busy then it will not restart automatically. A manual restart of the         module is required when not in use.   
-::
+:::
 
 -   The module can be restarted from the **Menu** > **Advanced** > **Modules** or from the console and **fs_cli** with following command.