Prepend In [x] in traceback with "Input " to avoid messing doctest

parsing

IPython/core/ultratb.py

@@ -185,7 +185,7 b' def _format_filename(file, ColorFilename, ColorNormal):'
 
     if ipinst is not None and file in ipinst.compile._filename_map:
         file = "[%s]" % ipinst.compile._filename_map[file]
-        tpl_link = "In %s%%s%s" % (ColorFilename, ColorNormal)
+        tpl_link = "Input %sIn %%s%s" % (ColorFilename, ColorNormal)
     else:
         file = util_path.compress_user(
             py3compat.cast_unicode(file, util_path.fs_encoding)

docs/source/whatsnew/development.rst

@@ -92,6 +92,13 b' Majority of our docstrings have now been reformatted and automatically fixed by'
 the experimental `Vélin <https://pypi.org/project/velin/>`_ project, to conform
 to numpydoc.
 
+Type annotations
+----------------
+
+While IPython itself is highly dynamic and can't be completely typed, many of
+the function now have type annotation, and part of the codebase and now checked
+by mypy.
+
 
 Featured changes
 ----------------
@@ -355,13 +362,13 b' The error traceback is now correctly formatted, showing the cell number in which'
     ...:     return 3 / 0
     ...:
 
-    In [2]: foo()
+    Input In [2]: foo()
     ---------------------------------------------------------------------------
     ZeroDivisionError                         Traceback (most recent call last)
-    In [2], in <module>
+    input In [2], in <module>
     ----> 1 foo()
 
-    In [1], in foo()
+    Input In [1], in foo()
         1 def foo():
     ----> 2     return 3 / 0