What is the ruling on rebuking someone who writes "إنشاء الله" (insha' Allah) as a single word, and what is the ruling if the rebuke can only be done through a public comment that contains a forbidden name?

Writing "إنشاء الله" (insha'a Allah) as one word is contrary to the rules of Arabic orthography and is considered an error. However, one should not condemn those who write it this way. Rather, this should be an occasion for offering advice and guidance, and there is no sin in leaving it as is.