If yyou remove the requirement to have the here "key" to be followed by
a newline, then you allow the possibility in inline here strings.

Consider some Scheme code that populates the registry:

  (registry-set-key #<<"HKEY_LOCAL_MACHINE\foo\bar..."  #<<!!some
abitrary text that does not have two bangs!!)

as opposed to the more tedious:

  (registry-set-key #<<"HKEY_LOCAL_MACHINE
\foo\bar...
"
#<<!!
some abitrary text that does not have two bangs
!!
)

Cheers,
Ray Blaak