LangRef: Don't refer to a 'generic' address space.

[arsenm]

Summary

Consistently call this the default address space.

[rjmccall]

Yes, that's a good idea.

[arsenm]

r299131

docs/LangRef.rst

::
       <result> = alloca [inalloca] <type> [, <ty> <NumElements>] [, align <alignment>]     ; yields type*:result
 
 Overview:
 """""""""
 
 The '``alloca``' instruction allocates memory on the stack frame of the
 currently executing function, to be automatically released when this
 function returns to its caller. The object is always allocated in the
-generic address space (address space zero).
+default address space (address space zero).
 
 Arguments:
 """"""""""
 
 The '``alloca``' instruction allocates ``sizeof(<type>)*NumElements``
 bytes of memory on the runtime stack, returning a pointer of the
 appropriate type to the program. If "NumElements" is specified, it is
 the number of elements allocated, otherwise "NumElements" is defaulted
""""""""""
       complicated, because subtracting this value from stack pointer would get the address
       one past the end of the most recent dynamic alloca.
 
       Although for most targets `llvm.get.dynamic.area.offset <int_get_dynamic_area_offset>`
       returns just a zero, for others, such as PowerPC and PowerPC64, it returns a
       compile-time-known constant value.
 
       The return value type of :ref:`llvm.get.dynamic.area.offset <int_get_dynamic_area_offset>`
-      must match the target's generic address space's (address space 0) pointer type.
+      must match the target's default address space's (address space 0) pointer type.
 
 '``llvm.prefetch``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Syntax:
 """""""
 
 ::