Python3.15.0a1 REPL : issue with pasting of Tab indented multiline code

Bug report

Bug description:

Misaligned output of pasted Tab-indented multiline code into the REPL:

~ $ python3.13
Python 3.13.8 (main, Oct 15 2025, 02:41:02) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PyQt6.QtWidgets import QApplication, QWidget
... from PyQt6.QtGui import QPainter, QColor, QPen
... from PyQt6.QtCore import Qt, QRect
... from cv2 import (
...     cvtColor,
...         COLOR_Lab2RGB,
...         COLOR_HSV2RGB_FULL,
...         COLOR_HLS2RGB_FULL,
... 
...         COLOR_RGB2Lab,
...         COLOR_RGB2HSV_FULL,
...         COLOR_RGB2HLS_FULL,
... 
... )
... 
>>> exit
~ $ python3.15
Python 3.15.0a1 (main, Oct 17 2025, 14:09:27) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PyQt6.QtWidgets import QApplication, QWidget
... from PyQt6.QtGui import QPainter, QColor, QPen
... from PyQt6.QtCore import Qt, QRect
... from cv2 import (
... 	cvtColor							,
                                                    ... 		COLOR_Lab2RGB				,
                                                                                         ... 		COLOR_HSV2RGB_FULL			,
... 		COLOR_HLS2RGB_FULL			,
                             ... 
                             ... 		COLOR_RGB2Lab				,
                                                                 ... 		COLOR_RGB2HSV_FULL			,
                                                                                           ... 		COLOR_RGB2HLS_FU... )			,
... 
>>> exit
~ $ 

CPython versions tested on:

3.15

Operating systems tested on:

Linux

Linked PRs

• gh-140697

Inizia riproducendo l'incollamento multilinea mostrato, con indentazione tramite Tab, nella REPL di Python 3.15 su Linux e confronta il relativo output con Python 3.13. La correzione è completa quando il codice multilinea incollato rimane correttamente allineato invece di acquisire grandi offset di spaziatura; l'issue fa riferimento alla PR collegata gh-140697.