[3.11] Python documents state elsewhere that a comma is not an operator (GH-98736) (#98757)

Python documents state elsewhere that a comma is not an operator, so calling it an operator here is confusing. See https://docs.python.org/3/reference/lexical_analysis.htmlGH-operators and https://docs.python.org/3/faq/programming.htmlGH-id22.
(cherry picked from commit d578aae)

Co-authored-by: Gerardwx <Gerardwx@users.noreply.github.com>

Author: miss-islington

Doc/reference/expressions.rst

@@ -154,7 +154,7 @@ tuple may or may not yield the same object).
    single: , (comma)
 
 Note that tuples are not formed by the parentheses, but rather by use of the
-comma operator.  The exception is the empty tuple, for which parentheses *are*
+comma.  The exception is the empty tuple, for which parentheses *are*
 required --- allowing unparenthesized "nothing" in expressions would cause
 ambiguities and allow common typos to pass uncaught.