message: Clear duplicate extensions
diff: @@ -17,6 +17,9 @@ export default class Extensions<Value> {
  return;
  }
  + // If extension is already defined, we remove it.
  + this.entries = this.entries.filter(([ext]) => ext != extension);
  +
  // Simple extension (.ts, .js, .json)
  if (extension.match(/^\.\w+$/)) {
  this.entries.push([extension, value]);
  