chore: enable linting ts files (#6351)

* chore: initial setup for linting ts

* chore: Temporarily disable most of the rules causing problems

* chore: fix autofixable problems.

* chore: ignore the last few files and rules

* chore: fix remaining lint errors

* chore: fix more small lint

* chore: run original rules on js files, new ts rules on ts files

* chore: use jsdoc style return in js files

* chore: add lint fix script

* chore: fix prefer-spread lint

* chore: fix no-invalid-this rule

* chore: fix no-unused-vars

* chore: fix trashcan lint

core/utils/string.ts

@@ -217,7 +217,7 @@ function wrapScore(
       lineLengths[lineLengths.length - 1]++;
     }
   }
-  const maxLength = Math.max.apply(Math, lineLengths);
+  const maxLength = Math.max(...lineLengths);
 
   let score = 0;
   for (let i = 0; i < lineLengths.length; i++) {

core/utils/style.ts

@@ -303,4 +303,4 @@ export function getContainerOffsetToScrollInto(
 
 export const TEST_ONLY = {
   getSizeInternal,
-}
+};

core/utils/svg.ts

@@ -22,7 +22,7 @@ goog.declareModuleId('Blockly.utils.Svg');
  * A name with the type of the SVG element stored in the generic.
  * @alias Blockly.utils.Svg
  */
-export class Svg<T> {
+export class Svg<_T> {
   /** @internal */
   static ANIMATE = new Svg<SVGAnimateElement>('animate');
   /** @internal */

core/utils/toolbox.ts

@@ -430,4 +430,4 @@ export function parseToolboxTree(toolboxDef: Element|null|string): Element|
 
 export const TEST_ONLY = {
   hasCategoriesInternal,
-}
+};