Remove (rejected) comment from DontReadFromInput

Ref: https://github.com/pytest-dev/pytest/pull/4996#issuecomment-479686487

src/_pytest/capture.py

@@ -693,13 +693,6 @@ class SysCaptureBinary(SysCapture):
 
 
 class DontReadFromInput:
-    """Temporary stub class.  Ideally when stdin is accessed, the
-    capturing should be turned off, with possibly all data captured
-    so far sent to the screen.  This should be configurable, though,
-    because in automated test runs it is better to crash than
-    hang indefinitely.
-    """
-
     encoding = None
 
     def read(self, *args):