Remove the word 'class' from annotation_string

Currently, 'foo(x: int)' results with annotation_string="<class 'int'>".
Change this to 'int'.

test/test_api/test_interpreter.py

@@ -342,7 +342,7 @@ def test_completion_params():
 
 @pytest.mark.skipif('py_version < 33', reason='inspect.signature was created in 3.3.')
 def test_completion_param_annotations():
-    # Need to define this function not directly in Python. Otherwise Jedi is to
+    # Need to define this function not directly in Python. Otherwise Jedi is too
     # clever and uses the Python code instead of the signature object.
     code = 'def foo(a: 1, b: str, c: int = 1.0) -> bytes: pass'
     exec_(code, locals())
@@ -354,6 +354,10 @@ def test_completion_param_annotations():
     assert [d.name for d in b.infer()] == ['str']
     assert {d.name for d in c.infer()} == {'int', 'float'}
 
+    assert a.description == 'param a: 1'
+    assert b.description == 'param b: str'
+    assert c.description == 'param c: int=1.0'
+
     d, = jedi.Interpreter('foo()', [locals()]).infer()
     assert d.name == 'bytes'