[x] If this PR changes anything about the main math_keyboard or example package
(also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change
on its own is not worth an update).
[x] If this PR includes a notable change in the math_keyboard package, I updated the version
according to Dart's semantic versioning.
Description
This PR adds a new icon for the symbols page and a fraction button to the second page of the keyboard
Checklist
Remove
If [...]
items that do not apply to your PR.math_keyboard
orexample
package (also README etc.), I created an entry inCHANGELOG.md
(## UPCOMING RELEASE
if the change on its own is not worth an update).math_keyboard
package, I updated the version according to Dart's semantic versioning.