Remove outdated information from Javadoc for PageableHandlerMethodArgumentResolver[Support]

[sryze]

The information about default parameter prefix seems outdated. It looks like that portion of the comment was added back in the days when the paging parameters were named page.page and page.size by default and now they are just page and size by default. Also there is a missing whitespace between identifiers in HTML docs:

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[pivotal-cla]

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[sryze]

Is there a way to sign the CLA without giving access to all account email addresses? I think it actually needs only one email.

[mp911de]

CLA isn't required as this is a trivial fix.

Thank you for your contribution. That's merged, polished, and backported now.