bpo-32452: clarify term 'brackets' in generator tutorial (GH-5079) (#5082)

Updates documentation for generator expressions in classes tutorial: Clarify usage of ambiguous term "brackets" by replacing with "square brackets". Updated subsequent lines to respect line breaks. (GH-5079)
(cherry picked from commit f190eb59e60e2ae7a7cbd396458389a7a076e0d3)
1 file changed