Fix TSLint nits

app/javascript/retrospring/features/settings/crop.ts

@@ -3,7 +3,7 @@ import Croppr from 'croppr';
 
 const readImage = (file, callback) => callback((window.URL || window.webkitURL).createObjectURL(file));
 
-export function profilePictureChangeHandler(event: Event) {
+export function profilePictureChangeHandler(event: Event): void {
   const input = event.target as HTMLInputElement;
 
   const cropControls = document.querySelector('#profile-picture-crop-controls');
@@ -32,7 +32,7 @@ export function profilePictureChangeHandler(event: Event) {
   }
 }
 
-export function profileHeaderChangeHandler(event: Event) {
+export function profileHeaderChangeHandler(event: Event): void {
   const input = event.target as HTMLInputElement;
 
   const cropControls = document.querySelector('#profile-header-crop-controls');

app/javascript/retrospring/features/settings/mute.ts

@@ -58,7 +58,7 @@ function createDeleteEvent(
   }
 }
 
-export function muteDocumentHandler() {
+export function muteDocumentHandler(): void {
   const submit: HTMLButtonElement = document.getElementById('new-rule-submit') as HTMLButtonElement;
   if (!submit || submit.classList.contains('js-initialized')) return;
 

app/javascript/retrospring/features/settings/theme.ts

@@ -15,7 +15,7 @@ const previewTheme = (): void => {
   generateTheme(payload);
 }
 
-const generateTheme = (payload: object): void => {
+const generateTheme = (payload: Record<string, string>): void => {
   const themeAttributeMap = {
     'primary_color': 'primary',
     'primary_text': 'primary-text',
@@ -88,7 +88,7 @@ export function themeDocumentHandler(): void {
 
     color.addEventListener('input', () => {
       clearTimeout(previewTimeout);
-      setTimeout(previewTheme, 1000);
+      previewTimeout = setTimeout(previewTheme, 1000);
     });
   });
 }