TSLint: re-enable callable-types rule

This rule specifies that if an interface defines a simple function, it
should be represented as a `type` rather than an `interface`.

src/lib/dom.ts

@@ -144,9 +144,7 @@ export function* elementsByXPath(xpath, parent?) {
 }
 
 /** Type for functions that can filter element arrays */
-interface ElementFilter {
-    (element: Element): boolean
-}
+type ElementFilter = (element: Element) => boolean
 
 /** Is the element of "substantial" size and shown on the page. The element
  * doesn't need to be in the viewport. This is useful when you want to
@@ -323,10 +321,7 @@ export function getSelector(e: HTMLElement) {
  * @param filters     filter to use (in thre given order) to further chose
  *                    items, or [] for all
  */
-export function getElemsBySelector(
-    selector: string,
-    filters: ElementFilter[],
-) {
+export function getElemsBySelector(selector: string, filters: ElementFilter[]) {
     let elems = Array.from(document.querySelectorAll(selector))
     let frameElems = getAllDocumentFrames().reduce((acc, frame) => {
         let newElems = []

tslint.json

@@ -3,7 +3,6 @@
   "rules": {
     "align": false,
     "arrow-parens": false,
-    "callable-types": false,
     "class-name": false,
     "cognitive-complexity": false,
     "comment-format": false,