XS✔ ◾ Update rule - Do you warn then call (#8558)

* Update rule.md

* Auto-fix Markdown files

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rules/warn-then-call/rule.md

@@ -27,12 +27,18 @@ guid: f1f96132-3b5d-43a6-9ed4-aed16f885875
 
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-It can be very jarring when somebody is called out of the blue and they are not expecting it. They might be deep in a task or talking to a client and by calling them their focus is getting disrupted. There should be "no hot calling".
+It can be very jarring when somebody is called out of the blue and they are not expecting it. They might be deep in a task or talking to a client and by calling them their focus is getting disrupted.
 
 Before calling someone, be sure [not to just say 'hello'](/no-hello).
 
 A good way to initiate a call is to warm them up by giving a warning (e.g. *“Calling you in 1 min to talk about the Northwind production site being down 💀.”*).
 
+::: greybox
+
+**Warm Calling:** Give a warning, then call.  
+**Hot Calling:** There's no need to give a warning, as the person you are calling is expecting your pre-arranged call.  
+:::
+
 <!--endintro-->
 
 ## The benefits of a warm call