Add quotes settings to eslintrc.

This matches prettier's settings, but should now warn in CI too.

Author: QuLogic

lib/matplotlib/backends/web_backend/.eslintrc.js

@@ -18,12 +18,14 @@ module.exports = {
         argsIgnorePattern: "^_",
       },
     ],
+    quotes: ["error", "double", { avoidEscape: true }],
   },
   overrides: [
     {
       files: "js/**/*.js",
       rules: {
         indent: ["error", 4, { SwitchCase: 1 }],
+        quotes: ["error", "single", { avoidEscape: true }],
       },
     },
   ],