ON Semiconductor Corp. made its pursuit of Allegro Microsystems Inc. public on Wednesday after disclosing an unsolicited $6.9 billion bid that includes debt.The chip company, which does business as Onsemi, is offering $35.10 per share for the target company, up from a September proposal of $34.50, it said in a statement. Allegro responded hours later to say it had reviewed the bid but found it “inadequateBloomberg Terminal.”...