style: add extensions to type imports

Author: keithamus

src/attr.ts

@@ -1,4 +1,4 @@
-import type {CustomElement} from './custom-element'
+import type {CustomElement} from './custom-element.js'
 
 const attrs = new WeakMap<Record<PropertyKey, unknown>, string[]>()
 type attrValue = string | number | boolean

src/controller.ts

@@ -1,8 +1,8 @@
 import {register} from './register.js'
 import {bind} from './bind.js'
 import {autoShadowRoot} from './auto-shadow-root.js'
-import {defineObservedAttributes, initializeAttrs} from './attr.js'
-import type {CustomElement} from './custom-element'
+import {defineObservedAttributes, initializeAttrs} from './attr.ts'
+import type {CustomElement} from './custom-element.js'
 
 /**
  * Controller is a decorator to be used over a class that extends HTMLElement.

src/register.ts

@@ -1,4 +1,4 @@
-import type {CustomElement} from './custom-element'
+import type {CustomElement} from './custom-element.js'
 
 /**
  * Register the controller as a custom element.