add multiline block comments

src/scanner.zig

@@ -272,6 +272,19 @@ pub const Scanner = struct {
                 // consume comments
                 if (self.match('/')) {
                     while (self.peek() != '\n' and !self.isAtEnd()) {
+                        _ = self.advance();
+                    }
+                } else if (self.match('*')) {
+                    // multiline block comments are messier to work with, but
+                    // we can still do it!
+                    while (true) {
+                        if (self.isAtEnd()) break;
+                        // check '*/'
+                        if (self.peek() == '*' and self.peekNext() == '/') {
+                            self.current += 2;
+                            break;
+                        }
+
                         _ = self.advance();
                     }
                 } else {