Emacs  : GNU Emacs 25.1.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.22.7)
 of 2017-02-07
Package: Org mode version 9.0.5 (release_9.0.5-325-g28b847 @
/tom/github/org-mode/lisp/)

Hello Nicolas,

thanks for encouraging me to deliver a patch.
The patch (i think the first in my life delivered to public)
contains a superfluous comment line first inserted then removed
other parts come from fill-paragraph.

I tried also to unify the spelling of M-TAB somtimes M-<TAB>, or variants.

$ git format-patch -2 HEAD --stdout --minimal >M-TAB_patch

made the attached file.

Thanks.