Enforce E741 (#22795)

Author: alimcmaster1

.pep8speaks.yml

@@ -8,5 +8,4 @@ pycodestyle:
     ignore:  # Errors and warnings to ignore
         - E402,  # module level import not at top of file
         - E731,  # do not assign a lambda expression, use a def
-        - E741,  # do not use variables named 'l', 'O', or 'I'
         - W503   # line break before binary operator

setup.cfg

@@ -15,7 +15,6 @@ parentdir_prefix = pandas-
 ignore =
     E402,  # module level import not at top of file
     E731,  # do not assign a lambda expression, use a def
-    E741,  # do not use variables named 'l', 'O', or 'I'
     W503,  # line break before binary operator
     C405,  # Unnecessary (list/tuple) literal - rewrite as a set literal.
     C406,  # Unnecessary (list/tuple) literal - rewrite as a dict literal.