Text effect keyboard toolbar for bold, italic, underline and strikethrough formatting

[garthvh]

What changed?

A button and toolbar is going to be added to devices running iOS 18 to allow them to add formatting to their text messages. The text message control on iOS already uses markdown to build the url and phone number links in messages so these already display properly.

Why did it change?

iOS 18 is adding Text Effects which adds a keyboard toolbar item to allow for adding GitHub flavored markdown in messages for bold, italic, strikethrough and underline.

How is this tested?

This is a iOS 18 only feature

Screenshots/Videos (when applicable)

Checklist

• My code adheres to the project's coding and style guidelines.
• I have conducted a self-review of my code.
• I have commented my code, particularly in complex areas.
• I have made corresponding changes to the documentation.
• I have tested the change to ensure that it works as intended.