perf annotate tui: Fix exit and RIGHT keys handling

As part of ongoing effort to reduce the coupling with libnewt, browsers
are being changed to return the exit key.

The annotate browser is not returning it as expected by builtin-annotate
when annotating multiple symbols (when 'perf annotate' is called without
specifying a symbol name).

Fix it by returning the exit key and also adding the RIGHT key as a exit
key so that going to the next symbol in the TUI can work again.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>