bpf, docs: Fix the code formatting in instruction-set

A minor typo fix to include "| BPF_LD" into its previous
code phrase:

``BPF_IND`` | BPF_LD --> ``BPF_IND | BPF_LD``
Signed-off-by: Shahab Vahedi <shahab@synopsys.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/b6120b31-3d1d-bf2d-2f2a-aa768d91257b@synopsys.com

Documentation/bpf/instruction-set.rst

@@ -351,7 +351,7 @@ These instructions have seven implicit operands:
  * Register R0 is an implicit output which contains the data fetched from
    the packet.
  * Registers R1-R5 are scratch registers that are clobbered after a call to
-   ``BPF_ABS | BPF_LD`` or ``BPF_IND`` | BPF_LD instructions.
+   ``BPF_ABS | BPF_LD`` or ``BPF_IND | BPF_LD`` instructions.
 
 These instructions have an implicit program exit condition as well. When an
 eBPF program is trying to access the data beyond the packet boundary, the