Filter out Keypad as a mod in sdl_key_names (#1678)

src/duckstation-nogui/sdl_key_names.h

@@ -333,14 +333,22 @@ std::optional<u32> ParseKeyString(const std::string_view key_str)
       break;
 
     const std::string_view mod_part = key_str.substr(pos, plus_pos - pos);
+    
+    // Keypad in SDL is not a mod and should always be the last + in the string
+    bool known_mod = false;
     for (const SDLKeyModifierEntry& mod : s_sdl_key_modifiers)
     {
       if (mod_part == mod.name)
       {
         modifiers |= static_cast<int>(mod.mod);
+        known_mod = true;
         break;
       }
     }
+
+    if (!known_mod)
+      break;
+
     pos = plus_pos + 1;
   }