Added a formating function to text_area

[baalimago]

This was needed to be added in order to implement formating according to the git 50/72 best practice for lazygit.

Pull request for 50/72 formating may be found here: https://github.com/jesseduffield/lazygit/pull/3095

It says here that the target branch should be "awesome", but I cannot find it. Deprecated documentation?