Win32: Fix right Shift scancode when using CJK IME

Fixes #2050

CONTRIBUTORS.md

@@ -19,6 +19,7 @@ video tutorials.
  - Nevyn Bengtsson
  - Niklas Bergström
  - Denis Bernard
+ - BiBi
  - Doug Binks
  - blanco
  - Waris Boonyasiriwat

README.md

@@ -221,6 +221,7 @@ information on what to include when reporting a bug.
    match event scancode (#1993)
  - [Win32] Bugfix: Instance-local operations used executable instance (#469,#1296,#1395)
  - [Win32] Bugfix: The OSMesa library was not unloaded on termination
+ - [Win32] Bugfix: Right shift emitted `GLFW_KEY_UNKNOWN` when using a CJK IME (#2050)
  - [Cocoa] Added support for `VK_EXT_metal_surface` (#1619)
  - [Cocoa] Added locating the Vulkan loader at runtime in an application bundle
  - [Cocoa] Moved main menu creation to GLFW initialization time (#1649)

src/win32_window.c

@@ -727,6 +727,10 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM l
             if (scancode == 0x146)
                 scancode = 0x45;
 
+            // HACK: CJK IME sets the extended bit for right Shift
+            if (scancode == 0x136)
+                scancode = 0x36;
+
             key = _glfw.win32.keycodes[scancode];
 
             // The Ctrl keys require special handling