message: docs: clarify how onOpen behaves for JB
diff: @@ -417,6 +417,8 @@ Define what to do when Gitpod detects a given port is being listened on.
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  +**Please note:** For JetBrains IDEs connected to Gitpod via [JetBrains Gateway](/docs/ides-and-editors/jetbrains-gateway) `open-preview` will behave exactly the same as `open-browser`, as there is no functionality for a web preview in the JetBrains IDE.
  +
  ### `ports[n].port`
  Define a single port or a range of ports, e.g. `3000-3100`.
  