feat(UI): move item notes to be with description, move MAGIC_FOCUS flag description to flag section

[chaosvolt]

Purpose of change

This implements a lil streamlining of some item UI stuff.

Describe the solution

C++ changes:

1. In item.cpp, removed the special bit in item::basic_info that places a description for the MAGIC_FOCUS flag directly above the item's description, as this is almost never actually important enough to be given such prominant placement.
2. Meanwhile, moved the check for notes inscribed on items out of item::final_info and into item::basic_info immediately below the item's basic description. This places it where you'd expect flavor text of this sort to be instead of being way down in its own dedicated section, separated by horizontal rules.

JSON changes:

1. Gave the MAGIC_FOCUS flag its orignal hardcoded text as its flag description.

Describe alternatives you've considered

Keeping item incriptions isolated by separators but still move them to directly below item description. I slapped some <info> on it so it doesn't blend in with the description though, so should be fine.

Testing

1. Checked affected JSON change for syntax and lint errors.
2. Compiled and load-tested.
3. Started up a world with Magiclysm added, spawned in a lesser staff of the magi.
4. Confirmed the magic focus text is now in the flag section, and that item description format hasn't been screwed up.
5. Spawned in a gun and checked that its description is normal, added a note to it and confirmed it correctly displays right under the description.
6. Spawned in a survivor's note, confirmed it shows the snippet correctly, and that slapping an inscription on it with a marker doesn't break anything.
7. Checked affected C++ changes for astyle.

Additional context

Checklist