docs: revise last chapters of customizations (#10480) #18

Job	Run time
setup	5m 43s
integration-tests-packages	17m 28s
Shard (0) HTTP Integration Tests	16m 40s
Shard (0) Unit Tests	12m 58s
Shard (1) HTTP Integration Tests	13m 10s
Shard (0) Module Integration Tests	14m 55s
Shard (1) Unit Tests	9m 10s
Shard (1) Module Integration Tests	13m 36s
unit-tests	1s
integration-tests-modules	1s
integration-tests-http	1s
	1h 43m 43s

Provide feedback