enable prefer const (#5113)

packages/babel-code-frame/test/index.js

@@ -1,6 +1,6 @@
-let assert = require("assert");
-let chalk = require("chalk");
-let codeFrame = require("..");
+const assert = require("assert");
+const chalk = require("chalk");
+const codeFrame = require("..");
 
 describe("babel-code-frame", function () {
   it("basic usage", function () {
@@ -119,7 +119,7 @@ describe("babel-code-frame", function () {
   });
 
   it("opts.linesAbove", function () {
-    let rawLines = [
+    const rawLines = [
       "/**",
       " * Sums two numbers.",
       " *",
@@ -143,7 +143,7 @@ describe("babel-code-frame", function () {
   });
 
   it("opts.linesBelow", function () {
-    let rawLines = [
+    const rawLines = [
       "/**",
       " * Sums two numbers.",
       " *",
@@ -166,7 +166,7 @@ describe("babel-code-frame", function () {
   });
 
   it("opts.linesAbove and opts.linesBelow", function () {
-    let rawLines = [
+    const rawLines = [
       "/**",
       " * Sums two numbers.",
       " *",
@@ -188,10 +188,10 @@ describe("babel-code-frame", function () {
   });
 
   it("opts.forceColor", function() {
-    let marker = chalk.red.bold;
-    let gutter = chalk.grey;
+    const marker = chalk.red.bold;
+    const gutter = chalk.grey;
 
-    let rawLines = [
+    const rawLines = [
       "",
       "",
       "",