documentation of rational_reconstruction incoherent with code

[zimmerma]

The documentation of rational_reconstruction says that an error *ZeroDivisionError?* is raised when no solution exists with the given bounds, but the code returns an error *ValueError?*.

[zimmerma]

Still there in 4.3.1:

sage: rational_reconstruction?
...

        exists, that pair is unique and this function returns it. If no
        such pair exists, this function raises ZeroDivisionError.

and:

sage: rational_reconstruction(29,105)
...
ValueError: Rational reconstruction of 29 (mod 105) does not exist.

Note also that in 4.3.1 a.rational_reconstruction? gives a different documentation, which does not mention what happens in case of error. Why are the documentations different?

[jdemeyer]

Fixed by #17180.