RFR: 7903962: Update IDEA plugin documentation

[Jorn Vernee]

On Thu, 6 Feb 2025 20:50:13 GMT, Oleksii Sylichenko <duke at openjdk.org> wrote:

> Update menu item location to open default settings window.
> 
> Current location is: `File -> New Projects Setup -> Settings for New Projects...`
> 
> Checked in "IntelliJ IDEA 2024.3.2.2 (Community Edition)".
> 
> ![Default settings menu location](https://github.com/user-attachments/assets/e9b94e74-5bea-476f-bcb1-f75ce76f3fc2)

When I try this, I now see the `jtreg` settings under the 'Other Settings' tab: 
![image](https://github.com/user-attachments/assets/abd1fc00-5e68-4690-b970-e352cdd7208d)

I think this would also be useful to mention in the docs.

I've created https://bugs.openjdk.org/browse/CODETOOLS-7903962, Please change the title of the PR to:


7903962: Update IDEA plugin documentation

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PR Comment: https://git.openjdk.org/jtreg/pull/247#issuecomment-2706581160
PR Comment: https://git.openjdk.org/jtreg/pull/247#issuecomment-2706594014