Update documentation of our internal Mumble service

wiki/src/contribute/working_together/roles/sysadmins.mdwn

@@ -281,8 +281,8 @@ Below, importance level is evaluated based on:
 
 ## Mumble
 
-* purpose: internal communication for the Fundraising team
-* access: Fundraising team members
+* purpose: internal communication for some internal teams
+* access: members of some internal teams
 * tools: [[!debpts mumble-server]]
 * configuration:
   - <https://github.com/voxpupuli/puppet-mumble>