doc: fix formatting and link in BPF library guide

[ upstream commit 85bd316 ]

Small improvements to the documentation based on Sphinx HTML doc output.

Fixes: 14b8f0b ("doc: add BPF library guide")
Fixes: b901d92 ("bpf: support packet data load instructions")

Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Acked-by: Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>

doc/guides/prog_guide/bpf_lib.rst

@@ -10,7 +10,7 @@ user-space dpdk application.
 
 It supports basic set of features from eBPF spec.
 Please refer to the
-`eBPF spec <https://www.kernel.org/doc/Documentation/networking/filter.txt>`
+`eBPF spec <https://www.kernel.org/doc/Documentation/networking/filter.txt>`_
 for more information.
 Also it introduces basic framework to load/unload BPF-based filters
 on eth devices (right now only via SW RX/TX callbacks).
@@ -48,9 +48,9 @@ For example, ``(BPF_IND | BPF_W | BPF_LD)`` means:
 .. code-block:: c
 
     uint32_t tmp;
-    R0 = rte_pktmbuf_read((const struct rte_mbuf *)R6,  src_reg + imm32,
-	sizeof(tmp), &tmp);
-    if (R0 == NULL) return FAILED;
+    R0 = rte_pktmbuf_read((const struct rte_mbuf *)R6,  src_reg + imm32, sizeof(tmp), &tmp);
+    if (R0 == NULL)
+        return FAILED;
     R0 = ntohl(*(uint32_t *)R0);
 
 and ``R1-R5`` were scratched.