Detect TypeScript rules defined with variable export

[bmish]

We detect many TypeScript rules already but we're failing to detect those using the TypeScript-specific export = rule syntax:

import {Rule} from 'eslint';

const rule: Rule.RuleModule = {
  meta: {},

  create(context): Rule.RuleListener {
    const source = context.getSourceCode();
    // ...
  }
};

export = rule;

Example: https://github.com/43081j/eslint-plugin-lit/blob/master/src/rules/no-duplicate-template-bindings.ts

[aladdin-add]

but export = rule is not an esm(?). I'd suggest the users move to the standard esm(e.g. export default rule).

[bmish]

Good point, updated title to reflect that this is only a TypeScript (not ESM) syntax, I still think we could support it.

https://www.typescriptlang.org/docs/handbook/modules.html#export--and-import--require

[aladdin-add]

ok, let's do it! 👍