[core] Check for throwing weapons when calculating pDIF

[sruon]

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• I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
• I have read and understood the Contributing Guide and the Code of Conduct.
• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Checks the ammo slot for Throwing Weapons if no ranged weapon was found.
Without it, Shurikens (and other Throwing weapons) are defaulting to Marksmanship, leading to inaccurate calculations.

Also made it explicitely log should the "no weapons case" occur, instead of defaulting to Marksmanship.

Credits to JudgeMack, Deft, Sakiro, Integrity, Koca (@lumokai), MadMike (@madmikeblvd), Fabfury (and probably missed a few) for testing and providing steps to reproduce.

Steps to test these changes

!changejob NIN 99
!additem shuriken 99

Breakpoint and throw, see skill type used.