[Feature Request] Add Intendation Information to Status Bar

[kevinmatthes]

Although this is just a "nice-to-have" functionality, it might help especially new users to become familiar with Zee: an information in the status bar which indentation settings are currently applied.

Some editors behave differently regarding the same coding language, especially when there are no official indentation conventions. This information might remind users to set their preferred indentation accordingly before continuing to make large changes in the respective source file.

Regarding the appearance and position, I would like to suggest to keep it simple with the first (majuscule) character of the respective indentation units, followed by the decimal representation of the indentation width without any delimiter. For instance, Haskell indents with S8, by default, while a language to be indented by a tab character spanning four columns would be indented by T4. A positioning next to the line and column information appears to be a sane plane.