Obvious change from int to bool. I took the opportunity to move the doc
to the header file.
gdb/ChangeLog:
* gdbtypes.h (get_array_bounds): Return bool, adjust some
callers. Move doc here.
* gdbtypes.c (get_array_bounds): Return bool
Change-Id: I8ed20298cb0927963c1f09b345966533d5ed06e2