Add tip when skipping to a not-yet-started call

src/groups/calls/commands.rs

@@ -238,7 +238,10 @@ impl Command<State, Extras> for SkipCommand {
                 .bye();
         } else {
             ctx.send()
-                .content("☎️ Skipped! Searching for a call...")
+                .content(format!(
+                    "**TIP:** {}\n☎️ Skipped! Searching for a call...",
+                    get_string_tips(ctx.prefix)
+                ))
                 .await?;
         }