\r instead of \n should work.
The page has a few helpful examples.
Regarding the more general issues , for scripts (as opposed to the vim
command line) , I prefer to be verbose and unambiguous. So , instead of
coming up with a special key combination to insert within the script a
special character , I would put instead in the script
execute "%substitute /></>\r</g"
Having said that , with a construct like vim -s script file ,
it is not obvious to me when exactly the commands in script will be
executed. Is it after loading file into memory ? What happens with
a construct like vim -s script file1 file2 ? I remember that somewhere
in the vim documentation it explains in which order events happen but
I don't remember where in the documentation. I would be wary of doing stuff
like vim -s script file is the script makes substantial changes in the
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