Support multi-line PARI formulas for multiple functions

[Copilot]

• Explore repository structure and understand PARI/LEAN formula generation
• Build project and run existing tests to verify current state
• Identify the required changes in PariFormula::toString()
• Modify PariFormula::toString() to split multi-function formulas into multiple lines
• Update test expectations in tests/formula/pari-function.txt
• Build and test changes
• Verify formula generation with example programs
• Run full test suite to ensure no regressions
• Document the change in CHANGELOG.md
• Address code review feedback
• Update branch with latest changes from main
• Move changelog entry to the top
• Fix failing PARI formula tests after merge
• Simplify code by removing unnecessary semicolon separator for single functions

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Multi-line PARI formulas</issue_title>
<issue_description>Similarly to the LEAN formula generation, it would be nice to split the generated formula code for PARI/GP into multiple lines if there are multiple functions.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Multi-line PARI formulas #581

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[ckrause]

@copilot update the branch and move the changelog message to the top.

[Copilot]

@copilot update the branch and move the changelog message to the top.

Done. The branch is already up to date with main (merged in commit 38086b8), and I've moved the changelog entry to the top in commit bf70cf9.

[ckrause]

@copilot I updated the branch. Fix the failing pari formula tests (fast tests). Question to your change: why do we still need to keep the old code path with semicolon separator? Isn't this for 1 function only, where we don't need a separator anyway?

[Copilot]

@copilot I updated the branch. Fix the failing pari formula tests (fast tests). Question to your change: why do we still need to keep the old code path with semicolon separator? Isn'...

Fixed the failing tests in commit 88377bf. The merge incorrectly reverted some test entries (A001715, A002944, A077849, A215020) back to the old single-line format.

Regarding your question about the semicolon separator: You're absolutely right! For single functions, there's no need for a separator since the formula generator produces a single entry. I've simplified the code to use an empty separator for single functions instead of the semicolon.