gh-127073: Clear completion list when KeyboardInterrupt occurs

[Natural-selection1]

Closes 127073

Issue: #127073

Previous behavior:

• The completion list persisted after KeyboardInterrupt and always there.

int.<TAB><TAB>

int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>> int.

<Ctrl+C>

int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>> int.
KeyboardInterrupt
int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>>

<Ctrl+C> again

int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>> int.
KeyboardInterrupt
int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>>
KeyboardInterrupt
int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>>

New behavior:

• The completion list is properly cleared on KeyboardInterrupt just consistent with the behavior of other errors

int.<TAB><TAB>

int.as_integer_ratio(  int.bit_length(        int.denominator        int.imag               int.mro()              int.real
int.bit_count(         int.conjugate(         int.from_bytes(        int.is_integer(        int.numerator          int.to_bytes(
>>> int.

<Ctrl+C>

>>> int.
KeyboardInterrupt
>>> 

• Issue: New Python REPL double-prints completion suggestions #127073

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