[matteozanettii]

Update functionsignatures by adding missing function signatures

Main reason

This PR updates the FSDA functionsignatures metadata by adding the function signatures that were still missing.

The current functionsignatures only documents getTickers, getYahoo, getFundamentals, and zscoreFS. This PR extends it to cover the remaining functions of the toolbox, so that the metadata is aligned with the current FSDA API and can be used reliably for documentation generation, argument validation, and developer tooling.

What changed

New function signatures added (24)

• cabc
• cascade
• clickableMultiLegend
• docrootFS
• existFS
• extendVEC
• findDir
• findFile
• isfunction
• m2ipynb
• medcouple
• multialign2ref
• multialignHeader
• openMatlabFileFromHTML
• pdfprotect
• position
• quickselectFS
• quickselectFSnw
• quickselectFSw
• removeExtraSpacesLF
• repDupValWithMean
• rescaleFS
• rows2varsFS
• RatcliffeObesrhelp

For cabc and cascade, the entries are included with empty inputs/outputs, since no arguments are currently documented for those functions.

Update to an existing entry

• zscoreFS: added 'modmadp' to the allowed values of the scale argument, bringing the signature in line with the implemented function.

Conventions

All added entries follow the existing schema format (_schemaVersion: "1.0.0") and use the same conventions already adopted in the file:

• required, namevalue, and ordered argument kinds
• type constraints (char, string, double, logical, table, struct, cellstr, ...)
• validation rules (scalar, vector, integer, >=1, <=1, numel=3, ...)
• allowed values expressed via choices={...}
• human-readable purpose fields

Impact

• Metadata-only update, no runtime or algorithmic changes.
• Improves completeness and consistency of functionsignatures.
• Makes the previously undocumented functions discoverable by tools that consume this metadata.

Notes

• Schema version unchanged.
• The JSON structure and naming conventions already present in the file are preserved.
• This PR only extends/updates entries; it does not remove or rename any existing one.