Optimistic conversion as if single line

[sungshik]

This PR:

• Disables the check for single-line-ness to optimistically convert multi-line productions to single-line rules
• To make the optimistic conversion work as expected, adds logic to sort productions based on their starting delimiter (if any)
• To make the sorting work as expected, refactors and extends the logic to compute inner/outer delimiters of productions
• Updates existing tests and adds new ones

[DavyLandman]

As far as I can understand, it looks good.

[sungshik]

Thank you Davy!