Changed default regex value in pandas.Series.str.replace not fully updated in docs

[juliangilbey]

In the docstring, we have:

pandas/pandas/core/strings/accessor.py

Line 1379 in 478d340

When `pat` is a string and `regex` is True (the default), the given `pat`

the phrase "(the default)" should be removed here as it is no longer the case in 2.0.0.

[StefanieSenger]

take

[MarcoGorelli]

yup, thanks for the report