Update rust-parser-generator-trait.js
Update rust-parser-generator-trait.js

Extract constant DEFAULT_ERROR_HANDLER.
DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax,DmitrySoshnikov/syntax