Changed formating in pillar example to avoid warning about wrong dictionary...

Changed formating in pillar example to avoid warning about wrong dictionary format from Salt. Added comment about type of token.

pillar.example

@@ -88,8 +88,8 @@ salt:
 
     # optional engine configuration
     engines:
-      slack:
-        token: xoxp-XXXXX-XXXXXXX
+      - slack:
+          token: xoxp-XXXXX-XXXXXXX   # use Slack's legacy API token
           control: True
           valid_users:
             - someuser
@@ -164,8 +164,8 @@ salt:
 
     # optional engine configuration
     engines:
-      slack:
-        token: xoxp-XXXXX-XXXXXXX
+      - slack:
+          token: xoxp-XXXXX-XXXXXXX   # use Slack's legacy API token
           control: True
           valid_users:
             - someuser