Option to disable the removing of trailing spaces

[Avol-V]

Currently there is no way to preserve trailing spaces, even when it's needed.

Maybe we need to preserve spaces in comments (for example, is a break line in markdown):

 /**
-·*·Some··
+·*·Some
 ·*·markdown
 ·*/

Or we want to preserve indentation level of the block:

 if·(·some·)
 {
 →some();
-→
+
 →return;
 }

In both cases dprint currently removes spaces, as you can see in difs.

It would be good if we could preserve user formatting here.
Or it can be more flexible solution with settings for trimming spaces with different situations (in empty line, in comment, in the end of the code lines).