Improve the About Page in Doxygen Documentation

[loricooperhdf]

From Elena's suggestions:

The “About” tab title is somewhat misleading. Renaming it to better reflect its contents—such as contributing to documentation or creating new content with Doxygen—would improve discoverability.

[byrnHDF]

We would probably need a single word to replace it.

[loricooperhdf]

I think the problem is with the content. It looks like the first couple of sections are generic doxygen content, and then some specific how-tos about our content. I think this whole page needs updated or re-written.

Here's the URL: https://support.hdfgroup.org/documentation/hdf5/latest/_about.html (I panicked and couldn't find it because it was behind the search box.)