Add demo for locale plugin configuration

[KeremAR]

Describe your use-case which is not covered by existing documentation.

The demos folder is missing an example for the Locale plugin (appearance:locale configuration). This plugin is commonly used to set Jenkins UI language and ignore browser preferences.

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

demos folder

[arushssingh]

Hi! I’d like to work on this issue, can I work?

[SantoshBarkade]

Hi, I would like to work on this issue.
Could you please confirm where the demo configuration should be added?

[Pindi-Srilasya]

Hi, I noticed that there has been no activity on this issue for some time.
I would like to work on adding the Locale plugin demo configuration if it is still needed.

[Kamalimurugesan12]

Hi, I’m new to Jenkins and open source. I would like to work on this issue. Can you guide me on where to add the demo?

[timja]

To anyone wanting to contribute, have a look at linked PRs before starting your own. Every PR has the same issue.

#2749 (review)