guard.format is not aware of one buffer can be attached to more than one windows

[haolian9]

hi! while reading the guard/format.lua, i found it does not save all the relevant window views but only the current one according to this line.
i have the confidence, haha, to say it can be improved due to this fact: when the buffer is being attached/showed in multiple windows, either in another split window or in another tabpage, their cursors need to be taken cared of too.