Update ModuleParserUtil to fix infinite loop

[griffio]

Fixes sqldelight/sqldelight#6064

➿ Prevent infinite loop when tokenType is null

ModuleParserUtil.custom_module_argument is a special hand written parser rule that creates a single token from multiple arguments and takes tokens until the next COMMA tokenType is reached.

This causes the Idea plugin to hang Ide process if tokenType is null.

jstack was used to identify 🌶️ hot thread in ModuleParserUtil while loop

Tested with local plugin build as hang only occurs with live IDE usage.
e.g

CREATE VIRTUAL TABLE dictionary_fts USING fts5(
    text,
        <--- type anything here and the IDE hangs
    content='',
    tokenize="unicode61 remove_diacritics 2"
);

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• CHANGELOG.md's "Unreleased" section has been updated, if applicable.