Relax rule: no-unused-vars (allow using ...rest to omit variables)

Fixes: standard/standard#800

The ignoreRestSiblings option is a boolean (default: false). Using a
Rest Property it is possible to “omit” properties from an object, but
by default the sibling properties are marked as “unused”. With this
option enabled the rest property’s siblings are ignored.

```js
// 'type' is ignored because it has a rest property sibling
var { type, ...coords } = data
```

eslintrc.json

@@ -129,7 +129,7 @@
     "no-unsafe-finally": "error",
     "no-unsafe-negation": "error",
     "no-unused-expressions": ["error", { "allowShortCircuit": true, "allowTernary": true }],
-    "no-unused-vars": ["error", { "vars": "all", "args": "none" }],
+    "no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": true }],
     "no-use-before-define": ["error", { "functions": false, "classes": false, "variables": false }],
     "no-useless-call": "error",
     "no-useless-computed-key": "error",