perf ui browser: Add a warn on unhandled hotkey helper

Will be used by the various browsers, looks like:

┌─Warning!───────────────────────────────────────────┐
29.15 │ 3c: cmpl $0x3,(%rbx) │ │
3.77 │ ↓ je 51 │'Ctrl+V' key not associated, use 'h' to see actions!│
16.59 │ movq 0x3b0(%rbx),%rdx │ │
30.65 │ movl 0x8(%rdx),%eax │ │
3.77 │ cmpl %eax,%edi │Press any key... │
0.25 │ ↓ jb 82 └────────────────────────────────────────────────────┘

Suggested-by: Ingo Molnar <[e-mail]>
Tested-by: Ingo Molnar <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/ui/browser.c

···
 	return key;
 }
 
+int ui_browser__warn_unhandled_hotkey(struct ui_browser *browser, int key, int timeout, const char *help)
+{
+	char kname[32];
+
+	key_name(key, kname, sizeof(kname));
+	return ui_browser__warning(browser, timeout, "\n'%s' key not associated%s!\n", kname, help ?: "");
+}
+
 int ui_browser__help_window(struct ui_browser *browser, const char *text)
 {
 	int key;

tools/perf/ui/browser.h

···
 
 int ui_browser__warning(struct ui_browser *browser, int timeout,
 			const char *format, ...);
+int ui_browser__warn_unhandled_hotkey(struct ui_browser *browser, int key, int timeout, const char *help);
 int ui_browser__help_window(struct ui_browser *browser, const char *text);
 bool ui_browser__dialog_yesno(struct ui_browser *browser, const char *text);
 int ui_browser__input_window(const char *title, const char *text, char *input,