The tech sector and other companies rushed to warn employees with H-1B visas against foreign travel as they responded to the chaos created by President Donald Trump’s move to slap a $100,000 application fee on the widely used program.Microsoft Corp., Alphabet Inc., Amazon.com Inc. and other tech companies sent messages to affected employees telling them to return to the US on Saturday and cancel any plans to depart the country after the White House said Friday that the new rules would go into effect on Sund ...