ISTANBUL — Turkish voters delivered a rebuke on Sunday to President Recep Tayyip Erdogan as his party lost its majority in Parliament in a historic election that dealt a blow to his ambition to rewrite Turkey’s Constitution and increase his power. The election results represented a significant setback to Mr. Erdogan, an Islamist who has steadily increased his power as president, a partly but not solely ceremonial post. After more than a decade as prime minister, Mr. Erdogan has pushed for more control of the judiciary and cracked down on any form of criticism, including prosecutions of those who insult...