[man] Update manpage for presets

[TurboTurtle]

The manpage for sosreport was previously missing documentation for the
new preset feature in 3.6.

This updates the manpage to include entries for add-preset, del-preset,
list-presets, and the --desc options.

Signed-off-by: Jake Hunsaker jhunsake@redhat.com

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Please place an 'X' inside each '[]' to confirm you adhere to our Contributor Guidelines

• Is the commit message split over multiple lines and hard-wrapped at 72 characters?
• Is the subject and message clear and concise?
• Does the subject start with [plugin_name] if submitting a plugin patch or a [section_name] if part of the core sosreport code?
• Does the commit contain a Signed-off-by: First Lastname email@example.com?

[bmr-cymru]

Ack, thanks