RFR: 8352612: No way to add back lint categories after "none" [v5]

[Maurizio Cimadamore]

On Fri, 11 Apr 2025 13:17:11 GMT, Archie Cobbs <acobbs at openjdk.org> wrote:

>> This PR relates to the `-Xlint:none` flag. Currently, it not only disables all lint categories as one would expect, but it also disables all non-mandatory warnings, period. In other words, `-Xlint:none` has `-nowarn` as a hidden side-effect. So for example, trying to do `-Xlint:none,serial` to enable only the `serial` lint category is futile: the category will be enabled but the warnings won't ever appear. This PR removes that hidden side-effect, and also clarifies some of the help output.
>
> Archie Cobbs has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Man page wording improvements per review comments.

Marked as reviewed by mcimadamore (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/24227#pullrequestreview-2760666020