Extending AI Actions (#2537)

* Added extending AI documentation

* Apply suggestions from code review

Co-authored-by: julitafalcondusza <[email protected]>
Co-authored-by: Adrien Dupuis <[email protected]>

* Manual review changes

* Generated PHP reference (#2539)

* Generated PHP API Reference

* Apply suggestions from code review

Co-authored-by: julitafalcondusza <[email protected]>
Co-authored-by: Adrien Dupuis <[email protected]>

* Manual review changes

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Co-authored-by: julitafalcondusza <[email protected]>
Co-authored-by: Adrien Dupuis <[email protected]>

* Regenerated reference

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Co-authored-by: julitafalcondusza <[email protected]>
Co-authored-by: Adrien Dupuis <[email protected]>