Update eslint config (#385)

* Simplify setup moving to @sinonjs/eslint-config@4

* Eslint & Prettier on check-types.ts

* eslint-mocha: no setup in describe

* eslint: remove ie11 references

* eslint: fix all errors in src

* eslint jsdoc: fix most non-TS related issues

The remaining issues are mostly to do with invalid types
that have been described using TypeScript, not JSDoc types.

We will most probably revert these to valid JSDoc and
forego of the produced TypeScript definitions.

Author: fatso83

.eslintrc.yaml

@@ -1,15 +1,5 @@
 extends:
-  - sinon
-
-plugins:
-  - ie11
-
-rules:
-  ie11/no-collection-args: error
-  ie11/no-for-in-const: error
-  ie11/no-loop-func: warn
-  ie11/no-weak-collections: error
-  prettier/prettier: off
+  - "@sinonjs/eslint-config"
 
 overrides:
   - files: "**/*-test.js"
@@ -20,7 +10,7 @@ overrides:
     rules:
       max-nested-callbacks: off
       mocha/no-exclusive-tests: error
-  - files: "**/*.ts"
+  - files: "test/**.ts"
     parserOptions:
       ecmaVersion: 2020
       sourceType: 'module'