Should ban side-effect imports

[jbreckmckye]

Under the ES spec it's possible to do side-effect only imports:

import './something.types.ts'

The AST for such an import looks like

"type": "ImportDeclaration",
"source": {
  "type": "Literal",
  "value": "./whatever",
  "raw": "'./whatever'",
  "range": [...]
},
"specifiers": [],
"importKind": "value",
"assertions": [],
"range": [...]

These cases won't be discovered by the ESLint plugin here, as the import rule checks specifiers - e.g. require-type-only-import/index.ts:L43. But a side-effect only import has no specifiers.