small doc bug in SystemABI

[Michael Zucchi]

Hi guys,

The class doc of SystemABI says:

  * Instances of this class can be obtained by calling {@link 
Foreign#getSystemABI()}

"Foreign" shouldn't be there?

I was just checking in on the state of panama after a long absence.   
The changes to the low level api such as removing ForiegnUnsafe look 
like an improvement and it didn't take much to convert some exploratory 
test code over.  I had another comment to make about librarylookup and 
classloaders clashing but it looks like that's being addressed right at 
this moment.

Dunno if i'll do much more for now (like the opencl binding), motivation 
and interest has completely evapourated. I'm just poking around to see 
if i can spark an interest something.

Cheers,
  Z