(!558) Dwarf fort exp

Description

Turns out Dwarven fortress was the only one with 300 exp reward. Lowered to 150 in order to match other forts.

 

Checklist

I have:

• Tagged my change with the ;,; comment block.
• Ensured that this merge request changes exactly one thing.
• Attached the proper labels to this merge request.
• Added the Merge Request number in the title. e.g. (!42)
• Added a devlog entry for this change.
• Tested my code.