Win32: Fix keypad equals key reported as unknown

Fixes #1315.
Closes #1316.
diff --git a/src/win32_init.c b/src/win32_init.c
index 660bb0a..d0c491f 100644
--- a/src/win32_init.c
+++ b/src/win32_init.c
@@ -309,6 +309,7 @@
     _glfw.win32.keycodes[0x053] = GLFW_KEY_KP_DECIMAL;
     _glfw.win32.keycodes[0x135] = GLFW_KEY_KP_DIVIDE;
     _glfw.win32.keycodes[0x11C] = GLFW_KEY_KP_ENTER;
+    _glfw.win32.keycodes[0x059] = GLFW_KEY_KP_EQUAL;
     _glfw.win32.keycodes[0x037] = GLFW_KEY_KP_MULTIPLY;
     _glfw.win32.keycodes[0x04A] = GLFW_KEY_KP_SUBTRACT;