Add curses.has_key submodule (#8421)

Author: Kevin Kirsche

stdlib/curses/has_key.pyi

@@ -0,0 +1,4 @@
+import sys
+
+if sys.platform != "win32":
+    def has_key(ch: int | str) -> bool: ...

tests/stubtest_allowlists/win32.txt

@@ -59,6 +59,7 @@ xxlimited
 # Modules that rely on _curses
 curses
 curses.ascii
+curses.has_key
 curses.panel
 curses.textpad