Good first documentation efforts for new contributors

[ravepossum]

Interested in contributing to pokeplatinum? Documenting the following smaller-scope files may be a good starting point:

• unk_02071CFC and ov5_021DD6FC - Map name pop-ups
• unk_0200A9DC - Screen brightness functionality (used in map transitions)
• unk_0200F174 - Screen transitions (fades, etc. can lead into unk_0200F85C which has a lot more content)
• unk_0201E3BC and unk_0201E190 - Math-related helper functions
• unk_0200C440 - Something to do with font printing
• unk_0201CED8 - 3D gfx culling
• unk_0201DBEC - VRAM transfer manager
• unk_0201E3D8 - Lower-level touch screen functionality

This list is a work-in-progress. If you tackle one of these items, please mention this issue in your PR so we know to update the list.