pycon lexer still reorders input

[jeanas]

Unfortunately, even after fe42aac and #2410, PythonConsoleLexer still reorders some inputs. For example, this:

>>> unterminated_traceback()
Traceback (most recent call last):
>>> 

is rendered as

>>> unterminated_traceback()
>>> 
Traceback (most recent call last):

[jeanas]

Also, some offsets are wrong. For example:

>>> from pygments.lexers import PythonConsoleLexer
>>> list(PythonConsoleLexer().get_tokens_unprocessed("""
... >>> print("a")
... a
... >>> print("b")
... b
... """)
... )
[(0, Token.Generic.Output, '\n'), (0, Token.Generic.Prompt, '>>> '), (4, Token.Name.Builtin, 'print'), (9, Token.Punctuation, '('), (10, Token.Literal.String.Double, '"'), (11, Token.Literal.String.Double, 'a'), (12, Token.Literal.String.Double, '"'), (13, Token.Punctuation, ')'), (14, Token.Text.Whitespace, '\n'), (16, Token.Generic.Output, 'a\n'), (0, Token.Generic.Prompt, '>>> '), (4, Token.Name.Builtin, 'print'), (9, Token.Punctuation, '('), (10, Token.Literal.String.Double, '"'), (11, Token.Literal.String.Double, 'b'), (12, Token.Literal.String.Double, '"'), (13, Token.Punctuation, ')'), (14, Token.Text.Whitespace, '\n'), (33, Token.Generic.Output, 'b\n')]

Note how it restarts to 0 in the middle of the stream.

[jeanas]

I think the simplest route here is to make PythonConsole a DelegatingLexer. It will make it a lot easier to reason about.