Move Capture classes from compat to capture and improve naming

Move {Passthrough,CaptureIO} to capture module, and rename Passthrough
-> Tee to match the existing terminology.

Co-authored-by: Ran Benita <ran@unusedvar.com>

testing/test_capture.py

@@ -804,10 +804,10 @@ class TestCaptureIO:
         assert f.getvalue() == "foo\r\n"
 
 
-class TestCaptureAndPassthroughIO(TestCaptureIO):
+class TestTeeCaptureIO(TestCaptureIO):
     def test_text(self):
         sio = io.StringIO()
-        f = capture.CaptureAndPassthroughIO(sio)
+        f = capture.TeeCaptureIO(sio)
         f.write("hello")
         s1 = f.getvalue()
         assert s1 == "hello"
@@ -818,7 +818,7 @@ class TestCaptureAndPassthroughIO(TestCaptureIO):
 
     def test_unicode_and_str_mixture(self):
         sio = io.StringIO()
-        f = capture.CaptureAndPassthroughIO(sio)
+        f = capture.TeeCaptureIO(sio)
         f.write("\u00f6")
         pytest.raises(TypeError, f.write, b"hello")