Carousel Examples: ad note informing authors that aria-rolesdescription uses the language of the page

[jongund]

Fixes #2355 by:

Adding a note to the carousel examples that the aria-roledescription value uses the language of the page, similar to labeling of controls.

Auto-Rotating Image Carousel Example with Buttons for Slide Control
Auto-Rotating Image Carousel with Tabs for Slide Control Example

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[jongund]

@jnurthen
I was cleaning up my old pull requests and this was one from about a year ago for the carousel examples. It adds an additional bullet to the Properties and States descriptions for the aria-roledescription property value to be in the language of the page. It only adds 2 lines of content to each carousel example file.

[jnurthen]

I prefer adding the suggested text.

[jongund]

@jnurthen
I added your suggest edit to include "... and should be localized by the author."

[mcking65]

Thank you @jongund, looks great, merging.