The term `looptri` was used ambiguously for both single & arrays.
The term `tri` was also used, causing `tri->tri`.
Use terms:
- `looptris` for an array or when dealing with multiple items.
- `looptri` is used when dealing with a single item.
- `lt` for a single MLoopTri variables & arguments.
This was already a convention but not followed closely.