cpython/Misc/NEWS.d/next/Core and Builtins/2024-06-19-19-54-35.gh-issue-120754.uF29sj.rst

Reduce the number of system calls invoked when reading a whole file (ex. ``open('a.txt').read()``). For a sample program that reads the contents of the 400+ ``.rst`` files in the cpython repository ``Doc`` folder, there is an over 10% reduction in system call count.