You can find documentation on AngelScript at the link below.
http://www.angelcode.com/angelscript/sdk/docs/manual/index.html
As for the as source itself, it is included in the repository at https://github.com/ArmageddonGames/ZeldaClassic.
Angelscript Documentation
Do you happen to know if there is a PDF that lists all the tokens, syntax, and the like?
Negative you'll need to compile it from doxygen.