separate messages by a newline

Author: pvdrz

compiler/rustc_error_messages/locales/en-US/parser.ftl

@@ -1,6 +1,7 @@
 parser-struct-literal-body-without-path =
     struct literal body without path
     .suggestion = you might have forgotten to add the struct literal inside the block
+
 parser-maybe-report-ambiguous-plus =
     ambiguous `+` in a type
     .suggestion = use parentheses to disambiguate