10$: error on writing = instead of => for lambda

[strager]

// error: write '=>' for arrow function
const FeatureCard = ({}) =(
  <div />
);

Inspiration: https://x.com/Legend_1234555/status/1921846618875216329

// Not an error (but maybe deserves a warning):
const FeatureCard = (x) =(
  <div />
);

// An error, but maybe tricky to diagnose properly:
const FeatureCard = (x) ={
  return 42;
};