PSI breaks on any parser error

[justint]

If the plugin's language parser fails at any point while reading a file, the file's PSI structure breaks which stops any dependent integrations (structure view, code folding, etc) from working. Ideally, the language definition should be as good as possible to avoid this, but I imagine I'll be continually tinkering on the language definition forever, especially if/when language changes come in the future.

The language definition should be updated to support recovering after any failures. How recovery works is defined in the Grammer-Kit: tutorial, how-to. This would ensure parsing failures would be less likely to cause other integrations to stop working.