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>