Adding '+' and '?' as legit characters in identifiers.

src/tokenizer.zig

@@ -553,9 +553,9 @@ pub const Tokenizer = struct {
                 },
 
                 .identifier => switch (c) {
-                    // Include "-" as an identifer token, this is the only difference
+                    // Include "-", "+" and "?" as an identifer token, this is the only difference
                     // with the Zig tokenizer.
-                    'a'...'z', 'A'...'Z', '_', '-', '0'...'9' => {},
+                    'a'...'z', 'A'...'Z', '_', '-', '+', '?', '0'...'9' => {},
                     else => {
                         if (Token.getKeyword(self.buffer[result.loc.start..self.index])) |id| {
                             result.id = id;