Give error if raw literal hits EOF, and stop removing .Using if it exists in flags and allowed_flags.

core/odin/parser/parser.odin

@@ -1564,10 +1564,6 @@ check_field_flag_prefixes :: proc(p: ^Parser, name_count: int, allowed_flags, se
 		}
 	}
 
-	if .Using in allowed_flags && .Using in flags {
-		flags &~= {.Using};
-	}
-
 	return flags;
 }
 

core/odin/tokenizer/tokenizer.odin

@@ -235,8 +235,8 @@ scan_raw_string :: proc(t: ^Tokenizer) -> string {
 
 	for {
 		ch := t.ch;
-		if ch == '\n' || ch < 0 {
-			error(t, offset, "raw string literal was not terminated");
+		if ch == utf8.RUNE_EOF {
+			error(t, offset, "string literal was not terminated");
 			break;
 		}
 		advance_rune(t);