Docs: make it clear that functions accept unlimited number of parameters

[sequba]

Context

Internal discussion: https://handsoncode.slack.com/archives/C04MQ954YPL/p1713780506089739

Types of changes

• [ ] Breaking change (a fix or a feature because of which an existing functionality doesn't work as expected anymore)
• [ ] New feature or improvement (a non-breaking change that adds functionality)
• [ ] Bug fix (a non-breaking change that fixes an issue)
• [ ] Additional language file, or a change to an existing language file (translations)
• [x] Change to the documentation

Checklist:

• [x] I have reviewed the guidelines about Contributing to HyperFormula and I confirm that my code follows the code style of this project.
• [ ] I have signed the Contributor License Agreement.
• [x] My change is compliant with the OpenDocument standard.
• [x] My change is compatible with Microsoft Excel.
• [x] My change is compatible with Google Sheets.
• [ ] I described my changes in the CHANGELOG.md file.
• [ ] My changes require a documentation update.
• [ ] My changes require a migration guide.

[github-actions[bot]]

Performance comparison of head (1f16a5bb16b5f22c0e869afd5543a790db3fb6e2) vs base (5485382a873ab1460c929a2d2865bdbf7a971676)

                                     testName |   base |   head | change
------------------------------------------------------------------------
                                      Sheet A | 485.96 | 507.22 | +4.37%
                                      Sheet B | 152.98 | 165.82 | +8.39%
                                      Sheet T | 141.32 | 145.53 | +2.98%
                                Column ranges | 493.49 | 497.17 | +0.75%
Sheet A:  change value, add/remove row/column |   14.8 |  14.63 | -1.15%
 Sheet B: change value, add/remove row/column | 134.94 | 125.77 | -6.80%
                   Column ranges - add column | 147.13 | 140.87 | -4.25%
                Column ranges - without batch |  445.9 | 453.42 | +1.69%
                        Column ranges - batch |  122.8 | 130.58 | +6.34%

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.37%. Comparing base (d7ee29f) to head (dc415f0). Report is 5 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1410   +/-   ##
========================================
  Coverage    97.37%   97.37%           
========================================
  Files          169      169           
  Lines        14428    14428           
  Branches      3099     3099           
========================================
  Hits         14049    14049           
  Misses         376      376           
  Partials         3        3