Undo incorrect fix of typos regarding 'an' article

Undo incorrect fix of typos regarding 'an' article
(revert part of commit cbde60d)

* src/atomic_ops/sysdeps/icc/ia64.h (AO_char_load_acquire): Fix typo
("an ld.acq") in comment.
* src/atomic_ops/sysdeps/loadstore/acquire_release_volatile.template
(AO_XSIZE_load_acquire): Likewise.
* src/atomic_ops/sysdeps/icc/ia64.h (AO_short_load_acquire,
AO_int_load_acquire): Add comment (similar to that of
AO_char_load_acquire).
* src/atomic_ops/sysdeps/loadstore/acquire_release_volatile.template
(AO_XSIZE_store_release): Fix typo ("an st.rel") in comment.
* src/atomic_ops/sysdeps/loadstore/acquire_release_volatile.h:
Regenerate.
* src/atomic_ops/sysdeps/loadstore/char_acquire_release_volatile.h:
Likewise.
* src/atomic_ops/sysdeps/loadstore/int_acquire_release_volatile.h:
Likewise.
* src/atomic_ops/sysdeps/loadstore/short_acquire_release_volatile.h:
Likewise.