Add check for tooltip-format for custom modules

[jones-josh]

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Issue https://github.com/Alexays/Waybar/issues/2914 tries to use tooltip-format on a custom module without a script. This change results in tooltip-format entries in config being used as the tooltip format, over any tooltip-related return from the output of a custom script if there is one.

This makes the most sense to me as it is the more visible change. If I see a tooltip-format entry in the config file, I expect that this is truth, not the output of a script in a different place. While it wouldn't be best practice to setting the tooltip in both places, I'd argue that a user would expect that their change to the config would be reflected in the case of using a 3rd party script they don't fully understand.

[jones-josh]

Of course will add to man and wiki as appropriate if approved of.

[Alexays]

LGTM

[jones-josh]

Will add to wiki once merged