Make code prettier

This updates ESLint and our shared eslint-config-openlayers to use Prettier.  Most formatting changes were automatically applied with this:

    npm run lint -- --fix

A few manual changes were required:

 * In `examples/offscreen-canvas.js`, the `//eslint-disable-line` comment needed to be moved to the appropriate line to disable the error about the `'worker-loader!./offscreen-canvas.worker.js'` import.
 * In `examples/webpack/exapmle-builder.js`, spaces could not be added after a couple `function`s for some reason.  While editing this, I reworked `ExampleBuilder` to be a class.
 * In `src/ol/format/WMSGetFeatureInfo.js`, the `// @ts-ignore` comment needed to be moved down one line so it applied to the `parsersNS` argument.

src/ol/Collection.js

@@ -2,27 +2,24 @@
  * @module ol/Collection
  */
 import AssertionError from './AssertionError.js';
-import CollectionEventType from './CollectionEventType.js';
 import BaseObject from './Object.js';
+import CollectionEventType from './CollectionEventType.js';
 import Event from './events/Event.js';
 
-
 /**
  * @enum {string}
  * @private
  */
 const Property = {
-  LENGTH: 'length'
+  LENGTH: 'length',
 };
 
-
 /**
  * @classdesc
  * Events emitted by {@link module:ol/Collection~Collection} instances are instances of this
  * type.
  */
 export class CollectionEvent extends Event {
-
   /**
    * @param {CollectionEventType} type Type.
    * @param {*=} opt_element Element.
@@ -45,10 +42,8 @@ export class CollectionEvent extends Event {
      */
     this.index = opt_index;
   }
-
 }
 
-
 /**
  * @typedef {Object} Options
  * @property {boolean} [unique=false] Disallow the same item from being added to
@@ -69,13 +64,11 @@ export class CollectionEvent extends Event {
  * @api
  */
 class Collection extends BaseObject {
-
   /**
    * @param {Array<T>=} opt_array Array.
    * @param {Options=} opt_options Collection options.
    */
   constructor(opt_array, opt_options) {
-
     super();
 
     const options = opt_options || {};
@@ -99,7 +92,6 @@ class Collection extends BaseObject {
     }
 
     this.updateLength_();
-
   }
 
   /**
@@ -185,7 +177,8 @@ class Collection extends BaseObject {
     this.array_.splice(index, 0, elem);
     this.updateLength_();
     this.dispatchEvent(
-      new CollectionEvent(CollectionEventType.ADD, elem, index));
+      new CollectionEvent(CollectionEventType.ADD, elem, index)
+    );
   }
 
   /**
@@ -240,7 +233,9 @@ class Collection extends BaseObject {
     const prev = this.array_[index];
     this.array_.splice(index, 1);
     this.updateLength_();
-    this.dispatchEvent(new CollectionEvent(CollectionEventType.REMOVE, prev, index));
+    this.dispatchEvent(
+      new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+    );
     return prev;
   }
 
@@ -259,9 +254,11 @@ class Collection extends BaseObject {
       const prev = this.array_[index];
       this.array_[index] = elem;
       this.dispatchEvent(
-        new CollectionEvent(CollectionEventType.REMOVE, prev, index));
+        new CollectionEvent(CollectionEventType.REMOVE, prev, index)
+      );
       this.dispatchEvent(
-        new CollectionEvent(CollectionEventType.ADD, elem, index));
+        new CollectionEvent(CollectionEventType.ADD, elem, index)
+      );
     } else {
       for (let j = n; j < index; ++j) {
         this.insertAt(j, undefined);
@@ -291,5 +288,4 @@ class Collection extends BaseObject {
   }
 }
 
-
 export default Collection;