Add documentation and fix templates

roles/matrix-server/templates/mautrix-whatsapp/config.yaml.j2

@@ -33,7 +33,7 @@ appservice:
     # Display name and avatar for bot. Set to "remove" to remove display name/avatar, leave empty
     # to leave display name/avatar as-is.
     displayname: WhatsApp bridge bot
-    avatar: mxc://maunium.net/NeXNQarUbrlYBiPCpprYsRqr
+    avatar: remove
 
   # Authentication tokens for AS <-> HS communication. Autogenerated; do not modify.
   as_token: "This value is generated when generating the registration"
@@ -42,6 +42,7 @@ appservice:
 # Bridge config. Currently unused.
 bridge:
   # {% raw %}
+  # protecting the go templates inside the raw section.
   # Localpart template of MXIDs for WhatsApp users.
   # {{.}} is replaced with the phone number of the WhatsApp user.
   username_template: whatsapp_{{.}}
@@ -51,8 +52,8 @@ bridge:
   # The following variables are also available, but will cause problems on multi-user instances:
   # {{.Name}}   - display name from contact list
   # {{.Short}}  - short display name from contact list
+  displayname_template: "{{if .Notify}}{{.Notify}}{{else}}{{.Jid}}{{end}} (WA)"
   # {% endraw %}
-  displayname_template: {% raw %}"{{if .Notify}}{{.Notify}}{{else}}{{.Jid}}{{end}} (WA)"{% endraw %}
 
   # The prefix for commands. Only required in non-management rooms.
   command_prefix: "!wa"