Update keyboard test doc for shift on Windows

Shift key handling was improved in 30b3f92, but the test documentation
wasn't updated.
diff --git a/doc/keyboard-test.txt b/doc/keyboard-test.txt
index d66e853..e839177 100644
--- a/doc/keyboard-test.txt
+++ b/doc/keyboard-test.txt
@@ -69,7 +69,7 @@
   - Alt, AltGr, Super [Win, X11]
   - Ctrl+AltGr [Win]
   - Meta [X11]
-  - Left/right identification (FIXME: broken for Shift on Win)
+  - Left/right identification (FIXME: broken release for Shift on Win)
   - CmdL => AltL, CmdR => SuperL, AltL => ModeSwitch, AltR => Level3Shift [OS X]
   - Hyper sends Super [X11]