message: Address PR suggestions
diff: @@ -12,7 +12,7 @@ import {markup} from '@romejs/string-markup';
  function extractPropertyKey(
  node: ObjectProperty | ObjectMethod | SpreadProperty,
  -) {
  +): string | undefined {
  if (
  (node.type === 'ObjectMethod' || node.type === 'ObjectProperty') &&
  node.key.type === 'StaticPropertyKey'
  @@ -27,10 +27,10 @@ function extractPropertyKey(
  return value.name;
  }
  - return value.value;
  + return String(value.value);
  }
  - return null;
  + return undefined;
  }
  export default {
  @@ -44,7 +44,7 @@ export default {
  for (const prop of node.properties) {
  const key = extractPropertyKey(prop);
  - if (key !== null) {
  + if (key !== undefined) {
  if (previousKeys.has(key)) {
  path.context.addNodeDiagnostic(prop, {
  category: 'lint/noDuplicateKeys',
  