Bug - DescriptionList - `termWidth` prop value is not applied

[dvail]

Describe the problem
The termWidth prop on the <DescriptionList> component does not work after updating from PF5 to PF6.

How do you reproduce the problem?
Visit the docs site and adjust the value of termWidth in the example. The width of the term does not change. https://www.patternfly.org/components/description-list#horizontal-using-custom-term-width-modifier

Expected behavior
Changing the termWidth updates the default size of the term in horizontal description lists.

Is this issue blocking you?
No, we can use the horizontalTermWidthModifier prop as an alternative that avoids this issue.

Screenshots
Not needed, see docs site example above.

Any other information?

I believe the cause of this is a malformed CSS class here: https://github.com/patternfly/patternfly-react/blob/main/packages/react-core/src/components/DescriptionList/DescriptionList.tsx#L9

The correct value should be

- `--${styles.descriptionList}_term-width`
+ `--${styles.descriptionList}__term--width`

as this change fixes the problem when the HTML is manually edited via dev tools on the docs site.

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Jira Issue: PF-3634