Win32: Fix right Shift scancode when using CJK IME

Fixes #2050

(cherry picked from commit 6dd526fb1a)

CONTRIBUTORS.md

@@ -18,6 +18,7 @@ video tutorials.
  - Nevyn Bengtsson
  - Niklas Bergström
  - Denis Bernard
+ - BiBi
  - Doug Binks
  - blanco
  - Waris Boonyasiriwat

README.md

@@ -133,6 +133,7 @@ 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] Disabled macOS fullscreen when `GLFW_RESIZABLE` is false
  - [Cocoa] Bugfix: A connected Apple AirPlay would emit a useless error (#1791)
  - [Cocoa] Bugfix: The EGL and OSMesa libraries were not unloaded on termination

src/win32_window.c

@@ -756,6 +756,10 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
             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