show-caches: Correct example output in documentation

Back in 2a00e18c71da ("show-caches: Make output more concise") when
we made the output use only 1 line per cache I failed to update the
documentation example to show the current format.

Change-Id: Ic8a7d44f9885f5f8404ff2ea9af8782454fc7549
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed