libgomp: Fix up OpenMP 5.2 feature bullet

libgomp: Fix up OpenMP 5.2 feature bullet

The previous bullet correctly mentions 5.2 added for Fortran
allocators directive which is a replacement of allocate directive
associated with ALLOCATE statement to differentiate it at parse time
from allocate directive as declarative one not associated with ALLOCATE
statement, but the deprecation bullet talks about non-existing allocator
directive.

2022-10-12  Jakub Jelinek  <jakub@redhat.com>

	* libgomp.texi (OpenMP 5.2): Fix up allocator -> allocate directive
	in deprecation bullet.