perf ui browser map: Provide feedback on unhandled hotkeys

Don't just eat unknown keys without providing visual feedback and
instructions on how to see which ones are assigned.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/Z_TYux5fUg2pW-pF@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/map.c

@@ -88,8 +88,10 @@ static int map_browser__run(struct map_browser *browser)
 		case '/':
 			if (verbose > 0)
 				map_browser__search(browser);
+			/* fall thru */
 		default:
-			break;
+			ui_browser__warn_unhandled_hotkey(&browser->b, key, 0, NULL);
+			continue;
                 case K_LEFT:
                 case K_ESC:
                 case 'q':