docs: Fix route lookup behavior description. #3303

Job	Run time
Prepare container	1m 6s
linux rpm fedora	6m 57s
osx clang --disable-ssl	2m 6s
linux gcc --disable-ssl	2m 35s
linux clang --disable-ssl	2m 37s
linux gcc test -300	9m 30s
linux gcc test 301-600	6m 21s
linux gcc test 601- unstable	6m 25s
linux clang test sanitizers -300	12m 38s
linux clang test sanitizers 301-600	9m 7s
linux clang test sanitizers 601- unstable	11m 21s
linux gcc test -ljemalloc -300	9m 54s
linux gcc test -ljemalloc 301-600	6m 37s
linux gcc test -ljemalloc 601- unstable	6m 43s
linux gcc system-test-dpdk dpdk -100	16m 58s
linux gcc system-test-dpdk dpdk 101- unstable	14m 54s
linux gcc system-test-userspace -100	15m 50s
linux gcc system-test-userspace 101- unstable	13m 49s
linux gcc system-test -100	18m 12s
linux gcc system-test 101- unstable	17m 56s
linux clang system-test sanitizers -100	20m 39s
linux clang system-test sanitizers 101- unstable	20m 0s
linux x86 gcc --disable-ssl	2m 43s
	3h 54m 58s

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