feat(types): add filter-input to HTMLElementTagNameMap

Adding `filter-input` to the global `HTMLElementTagNameMap` interface is the type-level equivalent of registering the tag in the global registry. Since it is now recognized as a globally-available element, it enables stronger types when using `<filter-input>` directly, or adding event listeners, etc.

Author: nberlette

src/index.ts

@@ -167,6 +167,9 @@ declare global {
   interface Window {
     FilterInputElement: typeof FilterInputElement
   }
+  interface HTMLElementTagNameMap {
+    'filter-input': FilterInputElement
+  }
 }
 
 if (!window.customElements.get('filter-input')) {