overlay: fixes for naive binding (#542)

## Description of change
Three bugs:

* Some keys are IME-dependent. Right Alt can be IME mode switch for
Japanese / Korean, and Right Ctrl is often the Kanji button.
* If you press modifiers like Ctrl during bind-many-naive, it will skip
over a button, because of broken for loop logic that ends up calling
`inc_buttons_many_index` too many times
* trying to cancel out of bind-many-naive with left and right mouse
buttons swap doesn't work

## Testing
Validating various IME. I don't have a keyboard in another language
though..

src/spice2x/cfg/button.cpp

@@ -58,8 +58,28 @@ std::string Button::getVKeyString() {
             return "Pause";
         case 0x14:
             return "Caps Lock";
+        case 0x15:
+            return "IME Kana/Hangul";
+        case 0x16:
+            return "IME On";
+        case 0x17:
+            return "IME Junja";
+        case 0x18:
+            return "IME Final";
+        case 0x19:
+            return "IME Hanja/Kanji";
+        case 0x1A:
+            return "IME Off";
         case 0x1B:
             return "Escape";
+        case 0x1C:
+            return "IME Convert";
+        case 0x1D:
+            return "IME Nonconvert";
+        case 0x1E:
+            return "IME Accept";
+        case 0x1F:
+            return "IME Mode Change";
         case 0x20:
             return "Space";
         case 0x21:
@@ -255,9 +275,9 @@ std::string Button::getVKeyString() {
         case 0xA3:
             return "Right Control";
         case 0xA4:
-            return "Left Menu";
+            return "Left Alt";
         case 0xA5:
-            return "Right Menu";
+            return "Right Alt";
         default:
 
             // check win API

src/spice2x/overlay/windows/config.cpp

@@ -1216,6 +1216,8 @@ namespace overlay::windows {
             } else {
 
                 // get new keyboard state
+                // these are async, and some keys generate multiple vKeys (e.g., VK_SHIFT, VK_LSHIFT)
+                // use care when iterating over the result (could result in torn reads)
                 bool keyboard_state_new[sizeof(buttons_keyboard_state)];
                 for (size_t i = 0; i < sizeof(keyboard_state_new); i++) {
                     keyboard_state_new[i] = GetAsyncKeyState(i) != 0;
@@ -1225,33 +1227,47 @@ namespace overlay::windows {
                 for (unsigned short int vKey = 0x01; vKey < sizeof(buttons_keyboard_state); vKey++) {
 
                     // ignore num lock escape sequence
-                    if (vKey != VK_NUMLOCK) {
-
-                        // check for key press
-                        if (keyboard_state_new[vKey] && !buttons_keyboard_state[vKey]) {
-
-                            // ignore escape
-                            if ((!escape_cancels_bind || vKey != VK_ESCAPE) &&
-                                (vKey != VK_LBUTTON || !ImGui::IsItemHovered())) {
-
-                                // bind key
-                                button->setDeviceIdentifier("");
-                                button->setVKey(vKey);
-                                button->setDebounceUp(0.0);
-                                button->setDebounceDown(0.0);
-                                button->setVelocityThreshold(0);
-                                ::Config::getInstance().updateBinding(
-                                        games_list[games_selected], *button,
-                                        buttons_page - 1);
-                                inc_buttons_many_index(button_it_max);
-                            } else {
-                                buttons_many_index = -1;
-                            }
-
-                            buttons_bind_active = false;
-                            ImGui::CloseCurrentPopup();
-                        }
+                    if (vKey == VK_NUMLOCK) {
+                        continue;
                     }
+
+                    // prefer VK_LSHIFT/VK_RSHIFT, VK_LCONTROL/VK_RCONTROL, VK_LMENU/VK_RMENU
+                    if (vKey == VK_SHIFT || vKey == VK_CONTROL || vKey == VK_MENU) {
+                        continue;
+                    }
+
+                    // check if key is newly pressed
+                    if (!(keyboard_state_new[vKey] && !buttons_keyboard_state[vKey])) {
+                        continue;
+                    }
+
+                    // don't bother checking GetSystemMetrics(SM_SWAPBUTTON), just check both
+                    const bool is_mouse_pressed = (vKey == VK_LBUTTON || vKey == VK_RBUTTON);
+
+                    // some key is newly pressed; process it here, which will result in a new bind
+                    // or a cancellation
+                    if (escape_cancels_bind && vKey == VK_ESCAPE) {
+                        // escape cancels out
+                        buttons_many_index = -1;
+                    } else if (is_mouse_pressed && ImGui::IsItemHovered()) {
+                        // left or right mouse click on top of cancel button
+                        buttons_many_index = -1;
+                    } else {
+                        // bind key
+                        button->setDeviceIdentifier("");
+                        button->setVKey(vKey);
+                        button->setDebounceUp(0.0);
+                        button->setDebounceDown(0.0);
+                        button->setVelocityThreshold(0);
+                        ::Config::getInstance().updateBinding(
+                                games_list[games_selected], *button,
+                                buttons_page - 1);
+                        inc_buttons_many_index(button_it_max);
+                    }
+
+                    buttons_bind_active = false;
+                    ImGui::CloseCurrentPopup();
+                    break;
                 }
 
                 // clean up