fix(npm): fix main path

Author: azu

package.json

@@ -12,7 +12,7 @@
   "name": "textlint-rule-ja-no-redundant-expression",
   "description": "冗長な表現を禁止するtextlintルール",
   "version": "1.0.0",
-  "main": "lib/textlint-rule-ja-no-redundant-expression.js",
+  "main": "lib/index.js",
   "scripts": {
     "test": "textlint-scripts test",
     "docs": "node tools/update-readme.js",