Extend existing superscript symbols on popup keys

[b02860de585071a2]

• Fixes https://github.com/Helium314/HeliBoard/issues/901
  • Adds superscript characters ⁵-⁹ and ⁰ (U+207{5-9,0}) to popup keys, as well as ⁽/⁾, ⁺/⁻, ⁼ (U+207{A-E}).
  • These may be accessed via their respective "standard" keys as listed:
  • Numbers: 5-9, 0
  • Symbols: (/),+/-, =

I have built and tested this on both an emulator and a physical Pixel 8 Pro, using standard EN-US QWERTY layout and Spanish QWERTY (with ñ, unsure of the technical name?).

Due to the minor nature of this change, I doubt it will introduce any complications, but further testing on lesser-used layouts is likely still needed.

[Helium314]

I'm ok with the number row changes, but the other keys seem to be more suitable for symbols_shifted than for symbols, or at very least should not be the first popup.

[b02860de585071a2]

the other keys seem to be more suitable for symbols_shifted than for symbols

⁼ is actually supposed to be in symbols_shifted, I just stuck it on the wrong key.

https://github.com/Helium314/HeliBoard/pull/902/commits/730d9e9314d99b7bfe7437947e029abc7e10bb07 should now preserve default popup key orders as shown below:

Current stable version screenshots

    

730d9e9 screenshots

    

This also keeps the grouping much more consistent with defaults (paren is now on the outside of the other types of brackets, etc). Let me know your thoughts.

[Helium314]

Thanks, this look fine.