Add the largest number possible to generate

[ldetwiler666]

It does not state any maximum value that you can generate to. For example, I could write Random(123456789) but I don't think its capable of generating up to 123 million different numbers. So, what is the biggest number that can be generated?

[per1234]

I think this would be solved by specifying the parameter types (#15). Then the max value could be found by consulting the reference page for that type.

FYI, in the future when you want to report an error or a request an improvement without knowing the specific fix that needs to be made, it would be more appropriate and easier for you to submit an issue report for this sort of thing rather than a pull request:
https://github.com/arduino/reference-en/issues

[SimonePDA]

The random number generator function creates values that should fit the range of the data type of the variable into which the value is stored. The max value should be chosen properly to avoid inconsistencies.
The max value, in any case, can't exceed the 32 bit representation limit. I'll add a note to random() to explain this.

thanks for pointing it out :)