bug#55102: By default, emacs lack the ability to change identation style on fly in menubar.

[shenlebantongying]

Hi,

Based on my observation, all other editors today can change indentation style 
on a convenient place (mostly some where in menu bar). Emacs should provide a 
menu item (in “Options") to force certain style of indentation (like tab or 
spaces, how long and how many?).

This is especially useful when working on multiple project which are usually 
having different style of indentation, and setting for each of them is 
burdensome.

There are enormous amount of webpages, blogs, posts on adjusting indentation of 
emacs. I think the need for them will be halved if there can be a Ad-hoc 
indentation style on menubar by default.