starter: Explicitly allow @# at the beginning of strings

Since we treat everything after # as comment identities of type
ID_KEY_ID couldn't be parsed otherwise, unless quoted.

src/starter/parser/lexer.l

@@ -79,7 +79,7 @@ static void include_files(parser_helper_t *ctx);
 	yy_push_state(str, yyscanner);
 }
 
-[^\"#= \t\n]+			{
+(@#)?[^\"#= \t\n]+			{
 	yylval->s = strdup(yytext);
 	return STRING;
 }

src/starter/tests/suites/test_parser.c

@@ -224,6 +224,9 @@ static struct {
 	{ "conn foo # asdf\n\tkey=val", TRUE, "val" },
 	{ "conn foo # asdf\n#\tkey=val", TRUE, NULL },
 	{ "conn foo # asdf\n\t#key=val", TRUE, NULL },
+	{ "conn foo # asdf\n\tkey=@#keyid", TRUE, "@#keyid" },
+	{ "conn foo # asdf\n\tkey=\"@#keyid\"", TRUE, "@#keyid" },
+	{ "conn foo # asdf\n\tkey=asdf@#keyid", TRUE, "asdf@" },
 	{ "conn foo # asdf\n\tkey=#val", TRUE, NULL },
 	{ "conn foo # asdf\n\tkey=val#asdf", TRUE, "val" },
 	{ "conn foo # asdf\n\tkey=\"val#asdf\"", TRUE, "val#asdf" },