pythongh-110938: More syntax tests for PEP695 funcs and classes (python#110986)

Author: sobolevn

Lib/test/test_syntax.py

@@ -1004,11 +1004,26 @@
    Traceback (most recent call last):
    SyntaxError: expected ':'
 
+   >>> def f[T]()
+   ...     pass
+   Traceback (most recent call last):
+   SyntaxError: expected ':'
+
    >>> class A
    ...     pass
    Traceback (most recent call last):
    SyntaxError: expected ':'
 
+   >>> class A[T]
+   ...     pass
+   Traceback (most recent call last):
+   SyntaxError: expected ':'
+
+   >>> class A[T]()
+   ...     pass
+   Traceback (most recent call last):
+   SyntaxError: expected ':'
+
    >>> class R&D:
    ...     pass
    Traceback (most recent call last):