Fixes unicode_map declaration example (#19450)

If the previous example was used the incorrect codepoints are produced.
Changes the order of arguments the declaration of the unicode_map

docs/feature_unicode.md

@@ -51,7 +51,7 @@ enum unicode_names {
     SNEK
 };
 
-const uint32_t PROGMEM unicode_map[] = {
+const uint32_t unicode_map[] PROGMEM = {
     [BANG]  = 0x203D,  // ‽
     [IRONY] = 0x2E2E,  // ⸮
     [SNEK]  = 0x1F40D, // 🐍