perf hists browser: Clarify top/report browser help

Clarify in the browser help that ESC in tui mode may go back to the
previous screen instead of just exiting (was not clear to me)

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20180406203812.3087-3-andi@firstfloor.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>