"dune top" output does not property escape strings #4231
Description
eg:
$ cat mlfip.mltop
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/applications/csharp_interface/.interfaces.objs/byte";;
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/applications/csharp_interface/.interfaces.objs/native";;
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/applications/csml/.csml_standalone.objs/byte";;
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/applications/csml/.csml_standalone.objs/native";;
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/private/a1a3_migration/.a1a3_migration.objs/native";;
#directory "c:\cygwin64\home\nojebar\mlfi2\_build/default/private/a1a3_migration/.a1a3_migration.objs/public_cmi";;