Fix comma text assignments

[vamshikrishnaramasamy]

Description

Fixes #6468. Quoted text containing commas, like name is "Hey, Hello!", now parses as a normal assignment instead of an assign_list. Bare comma-separated values still parse as lists.

How to test

• Verified generated Lark grammars for levels 4-12 parse this_is_not_a_list is "Hey, Hello!" as assign
• Verified generated Lark grammars for levels 4-12 still parse animals is dogs, cats, turtles as assign_list
• git diff --check

Note: I added a focused Lezer regression test, but did not run Cypress locally because npm ci did not finish in time and was interrupted.

[jpelay]

Hello, thanks for the PR, but sadly this fix won't hold. The level*-Total.lark files are automatically generated from the level*-Additions.lark files located on https://github.com/hedyorg/hedylang/tree/main/src/hedy/data/grammars (a different project). Please apply you fixes on the neccesary grammars targetting files on that repo.

Also take into account that if a grammar rule is not modified in the next level, it will not be present in the grammar file. Only modified rules. Therefore if you need to modify a rule on level 7, do so at that level and leave it like that unless the rule is further modified later.

[vamshikrishnaramasamy]

Thanks for the pointer. I moved this fix to the source grammar repo as requested: hedyorg/hedylang#13

Closing this generated-file PR so the fix can be reviewed in the right place.