[4.1] Description for class "Intro Image"

[Kostelano]

Pull Request for Issue #37560 (part 1).

Summary of Changes

The description of the parameter for the introductory image is missing (there is a description for the full one).

[Quy]

I have tested this item ✅ successfully on 23d846a

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[brianteeman]

I have tested this item ✅ successfully on 23d846a

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/37563.}

[Quy]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/37563.}

[Quy]

Thanks.

[wojsmol]

@Kostelano Please add partly after issue number in PR description.