ask-password: prefix password questions with lock and key emoji

It's pretty, and it highlights that the pw prompt is kinda special and
needs user input.

We suppress the emoji entirel if there's no emoji support (i.e. this
means we suppress the ASCII replacement), since it carries no additional
information, it is just decoration to highlight a line.

src/shared/ask-password-api.c

@@ -27,6 +27,7 @@
 #include "format-util.h"
 #include "fs-util.h"
 #include "io-util.h"
+#include "locale-util.h"
 #include "log.h"
 #include "macro.h"
 #include "memory-util.h"
@@ -430,6 +431,9 @@ int ask_password_tty(
         if (!message)
                 message = "Password:";
 
+        if (emoji_enabled())
+                message = strjoina(special_glyph(SPECIAL_GLYPH_LOCK_AND_KEY), " ", message);
+
         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
                 if (notify < 0)