[PR] Extend existing superscript symbols on popup keys

[b02860de585071a2]

Is your feature request related to a problem? Please describe.

(This issue is for a pull request)

Currently, only unicode superscript characters ¹-⁴ (U+00B{9,2-3}, U+2074) are accessible through key popups on the number row. Many keyboards also support ⁵-⁹ and ⁰ (U+207{5-9,0}).

Lacking these characters makes inputting certain text impossible - namely, scientific notation (e.g., 1.2345x10⁶⁷⁸⁹)

Describe the solution you'd like
I would like ⁵-⁹ and ⁰ to be accessible, as well as a handful of other commonly used math symbols: ⁽/⁾, ⁺/⁻, ⁼ (U+207{A-E}).

Use case
Primarily used for inputting text in scientific notation. Most useful for users in science/engineering fields.

Describe alternatives you've considered (if any)

• Copy/paste unicode characters: annoying and tedious
• Use another keyboard, i.e. Gboard: no